Mechanical ventilator with oxygen concentrator

ABSTRACT

A ventilator includes an enclosure, a tubing configured to receive an input gas, and a flow outlet airline in fluid communication with the tubing. The flow outlet airline includes an airline outlet. The ventilator further includes a breath detection airline including an airline inlet. The airline inlet is separated from the airline outlet of the flow outline airline. The ventilator further includes a pressure sensor in direct fluid communication with the breath detection airline. The ventilator includes a controller in electronic communication with the pressure sensor and an internal oxygen concentrator in fluid communication with the tubing. The internal oxygen concentrator is entirely disposed inside the enclosure.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority, and the benefit of, U.S. ProvisionalPatent Application 63/047742, filed Jul. 2, 2020, U.S. patentapplication Ser. No. 16/704,413, filed on Dec. 5, 2019, which in turnclaims priority, and the benefit of, U.S. Provisional Patent Application62/775,733, filed on Dec. 5, 2018, each of which is hereby incorporatedby reference in its entirety.

TECHNICAL FIELD

The present disclosure generally relates to a medical device, and moreparticularly, to a mechanical ventilator.

BACKGROUND

Conventional ventilators can lack portability and require continuousmonitoring of user conditions and manual adjustment of ventilatorsettings by health care personnel. In many cases, expensive ventilationmonitoring technologies such as CO2 capnography must be used inconjunction with a conventional ventilator, to determine effectivenessand make adjustments in settings during use. Conventional ventilatorcontrol methodology and ventilator configuration is not readilyadaptable for ventilator use with certain user conditions, for example,when the user is talking, during sleep, or when the user is connected toContinuous Positive Airway Pressure (CPAP) and/or Bilevel PositiveAirway Pressure (BiPAP) machines, for example, during sleep apneatherapy.

SUMMARY

A ventilator includes an enclosure, a tubing configured to receive aninput gas, and a flow outlet airline in fluid communication with thetubing. The flow outlet airline includes an airline outlet. Theventilator further includes a breath detection airline including anairline inlet. The airline inlet is separated from the airline outlet ofthe flow outline airline. The ventilator further includes a pressuresensor in direct fluid communication with the breath detection airline.The ventilator includes a controller in electronic communication withthe pressure sensor and an internal oxygen concentrator in fluidcommunication with the tubing. The internal oxygen concentrator isentirely disposed inside the enclosure.

A ventilator includes an enclosure, a tubing configured to receive aninput gas, and a flow outlet airline in fluid communication with thetubing. The flow outlet airline includes an airline outlet. The flowoutlet airline is configured to supply an output gas to a user via theairline outlet. The ventilator includes a breath detection airlineincluding an airline inlet. The airline inlet is separated from theairline outlet of the flow outline airline. The breath detection airlineis configured to receive breathing gas from the user during exhalationby the user via the airline inlet. The ventilator includes a pressuresensor in direct fluid communication with the breath detection airline.The pressure sensor is configured to measure breathing pressure from theuser, and the pressure sensor is configured to generate sensor dataindicative of breathing by the user. The ventilator includes acontroller in electronic communication with the pressure sensor. Thecontroller is programmed to detect the breathing by the user based onthe sensor data received from the pressure sensor. The ventilatorincludes an internal oxygen concentrator in fluid communication with thetubing. The oxygen concentrator is entirely disposed inside theenclosure.

The above features and advantages and other features and advantages ofthe present teachings are readily apparent from the following detaileddescription of the modes for carrying out the present teachings whentaken in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated into and constitute apart of this specification, illustrate implementations of the disclosureand together with the description, serve to explain the principles ofthe disclosure.

FIG. 1 is a schematic cross-sectional view of an adjustable airentrainment device using the Coanda effect.

FIG. 2 is a schematic cross-sectional view of a fixed air entrainmentdevice using the Jet Mixing Principle.

FIG. 3 is schematic illustration of a fixed air entrainment device thatuses the Jet Mixing Principle.

FIG. 4 is a schematic cross-sectional view of an air entrainment devicethat uses Venturi Vacuum with a manual valve to regulate the amount airentrainment.

FIG. 5 is a schematic illustration of a ventilator with an on-offsolenoid valve to modulate a compressed oxygen source.

FIG. 6 is a schematic illustration of a ventilator with proportionalcontrol valves and an air volume tank to modulate high pressure or lowpressure oxygen or compressed air source, wherein the ventilator isconfigured to detect a high pressure or low pressure oxygen source froma single input airline using two proportional control valves andmodulate the output gas.

FIG. 7A is a schematic illustration of a ventilator that uses anultra-low pressure gas source, and a turbine blower configured to addenergy to increase the pressure of the gas.

FIG. 7B is a schematic illustration of a ventilator that uses a positiveend-expiratory pressure (PEEP) valve.

FIG. 7C is a schematic illustration of a ventilator that uses an oxygenconcentrator.

FIG. 8A is a schematic cross-sectional view of an electronicallycontrolled check valve using pressure actuators, wherein theelectronically controlled check valve is shown in an OFF state.

FIG. 8B is schematic cross-sectional view of the electronicallycontrolled check valve of FIG. 8A shown in an ON state.

FIG. 9A is a schematic cross-sectional view of an electronicallycontrolled check valve using electromagnetic actuators, where the checkvalve is in a closed state.

FIG. 9B is a schematic cross-sectional view of the electronicallycontrolled check valve of FIG. 9A in an open state.

FIG. 9C is a front view of a latch of the electronically controlledcheck valve of FIG. 9A.

FIG. 10A is a schematic exploded view of an actuator for theelectronically controlled valve of FIG. 9A.

FIG. 10B is a schematic, cross-sectional perspective view of theactuator of FIG. 10A, wherein the actuator is a disengaged position.

FIG. 10C is a schematic, cross-sectional perspective view of theactuator of FIG. 10A, wherein the actuator is in an engaged position.

FIG. 10D is a schematic, cross-sectional perspective view of theactuator moving from the engaged position toward the disengagedposition.

FIG. 11 is a schematic diagram of an invasive ventilator, wherein thecarbon dioxide exhalation valve is inside the ventilator.

FIG. 12 is a schematic exploded, perspective view of the ventilator ofFIG. 11.

FIG. 13 is a schematic, perspective front view of the ventilator of FIG.11.

FIG. 14 is a schematic, perspective rear view of the ventilator of FIG.11.

FIG. 15 is a schematic diagram of an invasive ventilator, wherein theCO₂ exhalation valve is inside the ventilator.

FIG. 16 is a schematic diagram of a non-invasive ventilator circuitusing a breathing tube, an adapter, and oxygen tubing.

FIG. 17 is a schematic diagram of an invasive ventilator circuit using abreathing tube, an adapter, and oxygen tubing.

FIG. 18 is a schematic diagram of a ventilator with an internal oxygenconcentrator that allows the use of an external gas source.

FIG. 19 is a schematic diagram of a vacuum pressure swing adsorption(VPSA) system using check valves for on-demand oxygen production duringadsorption.

FIG. 20 is a schematic diagram of the VPSA system of FIG. 19 duringdesorption.

FIG. 21 is a schematic top view of a novel zeolite laminate adsorbentstructure.

FIG. 22 is a schematic diagram of a system for making the structure ofFIG. 21.

FIG. 23 is a schematic diagram of a ventilator with auto suctioning.

FIG. 24 is a schematic diagram of a mechanical oscillator pressure swingadsorption (PSA) and high frequency ventilation system.

FIG. 25A is a first schematic diagram of a piezoelectric oscillator PSAand high frequency ventilation system.

FIG. 25B is a second schematic diagram of a piezoelectric oscillator PSAand high frequency ventilation system.

FIG. 26 is a schematic diagram of a ventilator that can function asBiPAP or CPAP device, an O₂ concentration, and/or ventilator withdifferent modes.

FIG. 27 is a schematic diagram of a ventilator than can use a pulse doseoxygen concentrator as an O₂ source.

FIG. 27A is a schematic diagram of a portion of a ventilator that canallow switching between an O2 concentrator and compressed air using aninternal O2 blower and a ball valve/gear mechanism.

FIG. 27B is a schematic diagram of another portion of the ventilator ofFIG. 27A.

DETAILED DESCRIPTION

The foregoing summary, as well as the following detailed description ofcertain embodiments will be better understood when read in conjunctionwith the appended drawings. As used herein, an element or step recitedin the singular and preceded by the word “a” or “an” should beunderstood as not necessarily excluding the plural of the elements orsteps. Further, references to “one embodiment” are not intended to beinterpreted as excluding the existence of additional embodiments thatalso incorporate the recited features. Moreover, unless explicitlystated to the contrary, embodiments “comprising” or “having” an elementor a plurality of elements having a particular property may includeadditional elements not having that property.

FIG. 1 illustrates an adjustable air entrainment device 100 using theCoanda effect. The term “Coanda effect” means the tendency of a fluidjet to stay attached to a convex surface. The adjustable air entrainmentdevice 100 includes a first inlet 102 configured to receive compressedair or oxygen (i.e., the compressed gas CG). The first inlet 102 definesa first annular chamber 104 to direct the flow of the compressed gas CG.In an embodiment that utilizes oxygen as the compressed gas CG enteringthrough the first inlet 102, the adjustable air entrainment device 100may be used to create a ventilation mode with variable/adjustablefraction of inspired oxygen (FiO₂) without the need for an air blower orair-O₂ mixing chamber. In other words, the adjustable air entrainmentdevice 100 does not include an air blower or an air-O₂ mixing chamber.

The adjustable air entrainment device 100 further includes a secondinlet 106 configured to receive air or oxygen (i.e., the gas G). Thesecond inlet 106 defines a second annular chamber 108 in fluidcommunication with the first chamber 104 of the first inlet 102. Thesecond inlet 106 includes a second annular chamber 108 that defines thesecond annular chamber 106. As a consequence, the inlet cross-sectionaldimension CSD (e.g., inner diameter) of the second annular chamber 108continuously decreases from a first inlet end 110 to a second inlet end112 of the second inlet 106.

The adjustable air entrainment device 100 further includes a ring nozzle114 configured to receive the compressed gas CG from the first inlet 102and the gas G from the second inlet 106. Accordingly, the ring nozzle114 is in fluid communication with the first inlet 102 and the secondinlet 106. The ring nozzle 114 is configured to direct the flow of thecompressed gas CG and the gas G and may be adjusted through a threadedor other screw type mechanism. As such, a gap 116 between the firstannular chamber 104 of the first inlet 102 and the second annularchamber 108 of the second inlet 106 may be increased or decreased by theuser or an electromechanical mechanism, thereby increasing or decreasingthe amplification ratio of the air entrainment device 100. The ringnozzle 114 may be adjusted manually or automatically using anelectromechanical mechanism. By adjusting the ring nozzle 114, thepressure drop is converted into amplified high velocity laminar flow.The diameter of the ring nozzle 114 may be increased or decreasedthrough a screw type mechanism to further modify or adjust the airamplification ratio. The adjustable air entrainment device 100 mayfurther include a bushing or nut/washer of a fixed diameter orifice in astraight bore tube. The bushing or nut/washer may be threaded along thediameter of an outlet 118, which would create an orifice restriction andhence reduce the amount of air entrainment depending on the diameter ofthe orifice.

The adjustable air entrainment device 100 further includes a device body120 in fluid communication with the ring nozzle 114. The device body 120includes a convex inner surface 122 defining a third annular chamber124, thereby allowing the gas G and the compressed gas CG to flowthrough the ring nozzle 114 into the third annular chamber 124. Theconvex shape of the convex inner surface 122 of the device body 120allows the adjustable air entrainment device 100 to use the Coandaeffect. Therefore, the gas G and the compressed gas CG flowing into thethird annular chamber 124 stays attached to the convex inner surface122. The convex inner surface 122 of the device body 120 is tapered,thereby forming the convex shape of the convex inner surface 122.Specifically, the body cross-sectional dimension CSR (e.g., diameter) ofthe third annular chamber 124 continuously increases from a first bodyend 126 to a second body end 128 of the device body 120, therebyallowing the adjustable air entrainment device 100 to use the Coandaeffect. Due to the use of the Coanda effect, the device body 120 may bereferred to as an amplifier and is configured to amplify the airflowentering the adjustable air entrainment device 100.

The adjustable air entrainment device 100 further includes an outlet 118in fluid communication with the third annular chamber 124 of the devicebody 120. The outlet 118 may be configured as an orifice and receivesthe airflow amplified by the device body 120. The amplified airflow AFmay then exit the air entrainment device 100 through the outlet 118.Further, the airflow AF may be further amplified downstream of theoutlet 118 by entraining additional air from the surroundings at theexit of the outlet 118.

During operation, compressed gas CG (e.g., compressed air or compressedoxygen) enters through the first annular chamber 104 of the first inlet102 of the adjustable air entrainment device 100. Then, the compressedgas CG is throttled through the ring nozzle 114 at a high velocity andinto the third annular chamber 124 of the device body 120. While in thethird annular chamber 124, the airflow stays attached to the convexinner surface 122 of the device body 120, thereby creating a vacuum thatinduces air entrainment at the first inlet 102.

With reference to FIGS. 2 and 3, a fixed air entrainment device 200includes a funnel shaped tube 202 configured to receive compressed airor oxygen (i.e., compressed gas CG). Due to its funnel shape, the funnelshaped tube 202 creates a jet flow pattern. The fixed air entrainmentdevice 200 further includes a plurality of air entrainment ports 204 influid communication with the funnel shaped tube 202. In addition, thefixed air entrainment device 200 further includes an outlet tube 206 influid communication with the funnel shape tube 202. Each of the airentrainment ports 204 is configured to entrain a unidirectional flow(i.e., gas G) of room air in a high-pressure zone by creating alow-pressure zone at the outlet tube 206. The oxygen or air flowingthrough the funnel shape tube 202 is ejected through the outlet tube 206(see e.g., airflow AF). The ratio of air entrainment is mechanicallydesigned based on several variables, such as air entrainment port size,the shape and/or diameter of the funnel shaped tube 202 for the oxygengas source, and/or gaps between the funnel shaped tube 202 and theoutlet tube 206.

As shown in FIG. 3, the funnel shaped tube 202 may be configured as aninlet hose including a plurality of barbs 208 to facilitate connectionto an oxygen source. Additionally, the outlet tube 206 may be configuredas a hose fitting to facilitate connection to a breathing tube. Forexample, the outlet tube 206 may be configured as a 22-millimeterdiameter hose fitting to connect to and/or facilitate connection with astandard breathing tube, such as a continuous positive airway pressure(CPAP) tube or a single limb ventilator patient circuit.

During operation, the compressed air or oxygen (i.e., compressed gas)enters the funnel shaped tube 202 to create a jet flow pattern. The airentrainment ports 204 then entrain the unidirectional flow of room air(i.e., gas G) in a high-pressure zone by creating a low pressure zone atthe outlet tube 206.

With reference to FIG. 4, an adjustable air entrainment device 400 mayuse the Venturi effect. The adjustable air entrainment device 400includes a funnel shaped inlet 402 configured to receive compressed airor oxygen (i.e., compressed gas CG). The adjustable air entrainmentdevice 400 further includes a nozzle 404. During operation, thecompressed air or oxygen (i.e., compressed gas CG) enters the funnelshaped inlet 402 and then flows through the nozzle 404 to create a jetflow pattern. The adjustable entrainment device 400 further includes anair gap 406 downstream of the nozzle 403 and an air entrainment port 404in fluid communication with the nozzle 403. The air entrainment port 404is configured to receive room air (i.e., gas G) at atmospheric pressure.The turbulent air jet TJ exiting the nozzle 403 entrains room airthrough the air gap 406 and serves as the “motive fluid flow” to pull orcreate a vacuum at the air entrainment port 404. The adjustable airentrainment device 400 further includes a mixer outlet 408 in fluidcommunication with the air gap 406. The mixer outlet 408 has a Venturiprofile and is downstream of the air gap 406. The compressed air oroxygen (i.e., the compressed gas CG) plus entrained room air pulledusing a Venturi vacuum is then exhausted through the mixer outlet 408.The adjustable air entrainment device 400 may include a manual orelectrically actuated valve 410, which can be adjusted by a user or amachine to create an orifice restriction or vary the size of the airentrainment port 404, thereby allowing the user to increase or decreasethe amount of air entrainment using the Venturi vacuum. Hence, theadjustable air entrainment device 400 may be used as a variable airentrainment device. Moreover, the air gap 406 and/or air entrainmentport 404 may be increased or decreased using a slider mechanism (notshown), which can be used to affect the turbulence/velocity of themotive fluid flow/jet mixing profile as it enters the air gap 406,thereby increasing or decreasing the volume or flow rate of room airentrained via the Venturi vacuum effect.

With reference to FIG. 5, a ventilator 500 includes an on-off orelectronically controlled solenoid valve 502 configured to modulatecompressed oxygen or air sources. Accordingly, the solenoid valve 502has at least an open state and a closed state. The solenoid valve 502may be part of a valve arrangement 501. The valve arrangement 501 maytherefore include one or more of the solenoid valves 502. It is alsocontemplated that the valve arrangement 501 may include other types ofvalves. Hence, the ventilator 500 may include a single solenoid valve502 to minimize cost and weight. The ventilator 500 functions byreceiving input gas IG from an input gas source through a ventilatortubing 503. As non-limiting examples, the input source may be an aircompressor, air blower, stationary oxygen concentrator, portable oxygenconcentrator, air tank, and/or oxygen tank. A continuous flow of inputgas IG enters the ventilator 500 through the ventilator tubing 503, andwhen the solenoid valve 502 opens, the flow rate of input gas IG andoutput gas OG is the same or at least substantially the same.

The ON-OFF cycles of the solenoid valve 502 are controlled using acontroller 504, such as a microprocessor or microcontroller unit. Thecontroller 504 may be part of an electronic board 506, which can containadditional electronic components including but not limited to: powerelectronics, resistors, capacitors, alarms 508, and copper traces. Theelectronic board 506 may include one or more alarms 508. The alarms 508can, for example, be used to warn the user of one or more of thefollowing conditions: tubing disconnections, electrical or air supplyfailure, high peak airway pressure, auto-positive end-expiratorypressure (auto-PEEP), high gas supply pressures, and/or no spontaneousbreathing. Further, this electronic board 506 may be utilized as abattery management system for a portable ventilator device that isbattery powered.

The ventilator 500 can include an electrical power source 510, such as aportable rechargeable Li-Ion battery pack or another suitable portablebattery assembly. The electrical power source 510 (e.g., battery pack)may include a recharging interface 512, such as a port or cable, therebyallowing the electrical power source 510 to be recharged. Asnon-limiting examples, the recharging interface 512 may be a UniversalSerial Bus-C (USB-C), a USB, a micro-USB, or other charging interfaces.The electrical power source 510 may be electrically connected to theelectric board 506 to supply electricity to the controller 504 and thealarms 508.

This controller 504 may be in the form of an field-programmable gatearray (FPGA), a microcontroller (MCU), single board computer,application-specific integrated circuit (ASIC), programmable logiccontroller (PLC) on a chip, and/or other processing or computer hardwarethat can control the ON/OFF or OPEN/CLOSE cycles of a solenoid valve502. The solenoid valve 502 may be controlled using fluidic chips orother non-conventional or pneumatic methods of valve control, such asair cylinder actuations. For example, an air cylinder or pressureactuator 514 and a check valve may replace the electronically controlledsolenoid valve 502. As such, the cracking pressure of the check valvewould be higher than the input gas source IG and can only be openedusing an air cylinder or pressure actuator 514. The air cylinder orpressure actuator 514 may be electronically controlled to open at thebeginning or end of the respiration cycle (i.e., at inhalation) toprovide a ventilatory inspiratory positive airway pressure (IPAP) orpositive end-expiratory pressure (PEEP). This can be beneficial insituations where very low-pressure oxygen or compressed air sources areused, and where miniature electronically controlled solenoid valves havesmall orifices, in some cases as small as 0.009 inches diameter, wouldnot be effective. The miniature solenoid valves create significantorifice/flow restrictions that necessitate the use of high-pressureinput gas sources, in the range of 25-50 pounds per square inch (PSI).Check valves, on the other hand, generally have much larger orifices,such as 0.75 inch diameter, in small size form factors compared to theelectronically controlled valve counterparts. For example, a 7 mmorifice electronically controlled solenoid valve weighs about 1 poundand consumes approximately 13 W of power, which would make theventilator device bulky. By contrast, the ventilator 500 including theminiature air cylinder or pressure actuator 514 can rival a miniatureelectronically controlled solenoid valve 502 in terms of weight andpower consumption, while having larger orifices and allow the use oflower pressure gas sources than in other systems. Any numbers providedabove or below are only examples and should not be interpreted asfunctional limitations of the presently disclosed ventilator.

The ventilator 500 may include an oxygen or air tank 516, which isconfigured as a pressure source to deliver pressurized oxygen to thepatient for ventilatory support. The electrical power source 510 may beelectrically connected to the oxygen tank 516 and the electric board506. However, the ventilator 500 may be completely pneumaticallypowered. As such, a certain portion of the input gas IG may be used todrive an impeller, which would generate electrical energy that can powerthe controller 504 and other energy consuming components such as thesolenoid valve 502. However, other oxygen and/or pressure sources can beutilized such as continuous flow oxygen concentrators or aircompressors. Further, flow control software and the hardware of thesolenoid valve 502 may be utilized such that gas sources with differentpressure values can be interchanged while maintaining a consistent ordynamically adjusted controlled gas flow rate to the patient. A pressureactuator may be built into the portable ventilator 500, allowing a pulsedose oxygen concentrator to be utilized. This pressure actuator canperiodically trigger a pulse dose oxygen conserver at a fixed rate, suchas once every 4 seconds or 15 “breaths per minute”. The pulse doseoxygen bursts would accumulate inside an air volume tank connected to orinside the ventilator 500. The ventilator 500 then outputs the oxygenpulse from the air volume tank in a manner that ventilatory supportwould be provided the patient. The ventilator 500 may have two modes ofoperation, namely: (1) an oxygen conserver mode; and 2) ventilator mode.The ventilator mode may also have ventilator submodes of operation.These ventilation submodes may be selected by the patient, physician,and/or manufacturer and may include assist control, tidal assistventilation, and/or synchronized intermittent mandatory ventilation(SIMV). The pressurized output gas OG may be outputted in a plurality ofdifferent waveforms, such as descending ramp, ascending ramp,sinusoidal, and/or square wave form, among others. Further, theseventilator gas output waveforms and flow rates may be adjusted based onbreathing airway pressure and/or flow measurements from a second lumenairline. In the presently disclosed ventilator 500, the flow control andbreathing measurements are separately obtained via dual lumen airlines.This dual lumen airline setup prevents electrical signal interferenceand saturation of the gas output pressure/flow and the breathingmeasurement pressure/flow sensor sensors found in prior art oxygenconserving devices and ventilators. Further, this also allows for theuse of much more sensitive pressure sensors for detecting breathing. Inother mechanical ventilators, single lumen tubes are used and, as such,the flow output and breath “triggering” or detection are done in thesame airline. Further, in other mechanical ventilators, only inhalationis detected. In other mechanical ventilators, exhalation and inhalationberating flows are spearhead using one-way check valves which comprisethe dual limb ventilator circuit. In the mechanical ventilators (e.g.,ventilator 500) of the present disclosure, the proximal pressure line isbidirectional (i.e., there are no check valves) and, as such, there isno pressure or flow “triggers” but rather pattern in breathing aremathematically computed based on nasopharynx pressure and/or breathdetection sensor waveforms. In experimental use, by positioning thepressure sensors for breath detection in a separate lumen from the lumenused for gas output, it was found six times (6×) more sensitive pressuresensors can be utilized with a dual lumen setup for detecting breathingcompared to single lumen pressure sensor. The ventilator 500 may alsohave rest, exercise, and/or sleep settings.

The flow rate of this continuous gas output to the patient (i.e., theoutput gas OG) is measured using a flow sensor 518. This flow sensor 518may comprise a plurality of sensor methodologies. For example, the flowsensor 518 may utilize the thermo-transfer principle, also known as thecalorimetric principle, to measure large ranges of gas flow rates whenthe gain factor of the flow sensor 518 is specifically calibrated andtested, such that the sensor output is amplified and two point trimmedat zero flow as well as a secondary flow rate point to optimizelinearity within a certain flow rate range, such as 0-40 standard literper minute (SLPM) gas flow. Under this thermo-transfer principle, insidethe flow sensor module 518, a temperature sensor (not shown) is heatedperiodically by a heater element (not shown). The flowing gas absorbsheat energy and conducts it away. The resulting temperature change is anindication of flow, which translates to an analog voltage value that isthen correlated to a flow output curve based on experimental data fromthe original equipment manufacturer (OEM) or sensor manufacturer duringcalibration and/or testing. Generally, this flow sensor 518 is aflow-through type sensor, wherein the flow sensor 518 includes a barbfitting inlet that connects to the oxygen or compressed air tubing 503,as well as a barb outlet to the flow outlet airline 520 with minimalresistance of fluidic loss. This flow outlet airline 520 can connect toa 22 mm breathing tube, hose barb, adapter, or other tubing connectionthereafter. Further, this flow outlet airline 520 may also be fluidlycoupled to an air entrainment device 522 described above in FIGS. 1-4.The flow sensor 518 can alternatively be other types of sensors, suchas: turbine-type flow meters, rotometers, and membrane baseddifferential pressure and temperature sensors that can be used tocalculate flow rates, which can work especially well for laminar type orlarge volume/low pressure flows. the flow outlet airline 520 includes anairline outlet 521.

In certain embodiments, while using the oxygen or air tank 516, a bolusor partial bolus of oxygen or compressed air can be output to thepatient at the beginning of their inspiration or end of theirexpiration. The peak inspiratory flow demands are the highest,potentially maximizing effective gas exchange in the lungs. This flowrate output from an air or oxygen tank 516 is not directly controlled,but rather is determined based on the orifice size/flow restriction ofthe solenoid valve 502 at a certain pressure. For example, with a 10PSIG pressure gas source in the air or oxygen tank 516, the output flowrate through a 0.009 inch diameter orifice electronically controlledsolenoid valve 502 in a completely open state would be 30 liters perminute (LPM), and with a 50 PSIG pressure gas source in the air oroxygen tank 516, the flow rate output would be 100 LPM. After the bolusvolume, for example 50 mL at a flow rate of 30 LPM, from the air oroxygen tank 516 is outputted to user through the flow outlet airline520, a continuous flow of input gas IG from the input gas source, forexample 2 LPM, until the end of the useful phase of respiration such as70% inhalation time, may follow. Then, the electronically controlledsolenoid valve 502 closes.

During operation, user spontaneous breathing is detected using aseparated breath detection airline 524 and an ultra-sensitive pressuresensor 526 for measuring breathing pressures (e.g., nasopharynxpressure). The breath detection airline 524 includes airline inlet 525.The airline inlet 525 is separated from the airline outlet 521 of theflow outlet airline 520 to minimize interference and therefore increasethe accuracy of the pressure sensor 526. The pressure sensor 526 is influid communication with the breath detection airline 524. This breathdetection airline 524 is configured to be connected to a 22 mm breathingtube, hose barb, adapter, or other tubing connection. The breathdetection airline 524 is not in fluid communication with the flow outletairline 520. By fluidly separating the breath detection airline 524 fromthe flow outlet airline 520, nasopharynx pressures can be measuredwithout signal interference from the pressure/flow output from theventilator 500, which would otherwise saturate the ultra-sensitivepressure sensor 526 required to measure nasopharynx pressures. In otherventilators and oxygen concentrators, a single airline is generallyutilized in which a flow or pressure trigger threshold, ex. −0.13 cm H₂Opressure, is used to determine the start of inhalation. This generallycreates substantial lag in the ventilator gas output or false breathingtriggers. Further, this necessitates the use of far less sensitivepressure sensors to prevent the pressure sensor from getting saturatedfrom the output flow gas from the ventilator. Also, if flow is triggeredbased on a flow ramp, there can still exist substantial signalinterference using a single airline.

In the presently disclosed ventilator 500, a breath detection softwareis used to predict transitions in breathing states and breathing timestates, for example: transition from inhale to exhale, 70% inhalationtime, transition from exhale to inhale, predicted PEEP based on % ofexhalation. This breath detection software functions by measuringnasopharynx pressures using a separated breath detection airline 524,then storing the voltage values from the pressure sensor 526 in thecontroller 504 (e.g., microcontroller) RAM or EEPROM. For this reason,the controller 504 is in electronic communication with the pressuresensor 526. Breath transition states and timing predictions are detectedthrough one or more mathematical calculations involving the pressuresensor voltage data including but not limited to: data filtering,differentiation, integration, linear regression analysis andlinearizations, moving average calculations, Taylor seriesapproximations, steady state error compensation, model predictivecontrol, proportional control, fuzzy control theory, ODEs, radial basisfunctions, quadratic-program approximation, feedforward control,adaptive control, PI and/or PID control, SISO control schema, andLaplace transformations. A moving average calculation may be used suchthat, if the filtered pressure sensor data falls below the movingaverage, a transition from an inhale to an exhale is predicted.

Other sensors can also be used independently, in combination with, or toreplace the pressure sensor(s) 526 described herein to measure datatrends in breathing, implement predictive breath detection softwarealgorithms, and/or actuate at certain threshold values and/or rampsincluding but not limited to: flow sensors, CO2 gas concentrationsensors, O2 gas concentration sensors, temperature sensors, humiditysensors, volume sensors, and/or acoustic sensors. This breath detectionis used to determine when to output ventilator gas, which can includecompressed air, oxygen, or a mixture thereof, to the patient at thecorrect time in order to provide pressure/ventilatory support, as wellas facilitate effective lung gas exchange, ventilation, and managearterial blood gases (ABGs) such as PaCO₂ and PaO₂. Accordingly, thepressure sensor 526 is configured to generate sensor data indicative ofbreathing by the user, and the controller 504 is programmed to detectthe breathing of the user based on the sensor data received from thepressure sensor 526.

The components and electromechanical subassemblies of the ventilator 500are contained within an electronics enclosure 528, which can bemanufactured using a plurality of manufacturing methods including butnot limited to: injection molding, 3D printing, CNC machining, sheetmetal fabrication, PCBA, wire harnessing, and other manual or automatedmanufacturing techniques not described herein.

With reference to FIG. 6, a ventilator 600 includes one or moreelectronically controlled proportional control valves 602, 605 and anair volume tank(s) 616. The ventilator 600 is similar to the ventilator500, except for the features described below. These proportional controlvalves 602, 605 and air volume tanks 616 can be configured in numerousways for different purposes. The proportional control valves 602, 605are part of a valve arrangement 601 and can be fluidly coupled inparallel. One or more proportional valves 602, 605 may be used to outputa high pressure or low pressure oxygen/compressed output gas OG.Further, the ventilator 600 can detect a high pressure or low pressureoxygen source from a single input airline (i.e., tubing 503) using ahigh pressure proportional control valve 605 and a low pressureproportional control valve 602 to modulate output gas OG. To do so, theventilator 600 may include an input pressure sensor 630 to detect inputgas source pressure (i.e., the pressure of the input gas IG), or byutilizing one proportional valve 602 or 605 in the fully open positionfor a short time period, such as 50 milliseconds, to determine the flowrate output detected by the flow sensor 518. The flow rate can be usedto calculate the pressure of the input gas IG based on the orificediameter/flow restriction of the electronically controlled proportionalcontrol valves 602, 605.

When the proportional control valve(s) 602, 605, are closed, the inputgas IG of continuous flow can accumulate in the air volume tank 616.This can serve the following purposes: bolus output at the beginning ofthe useful phase of respiration, a method of conservingoxygen/compressed air, and/or a method for proportional flow control ofthe gas output, such that a high output flow rate (e.g., 200 LPM) can beoutputted from a low input flow rate (e.g., 6 LPM). Depending on theapplication, the size/volume specifications of the air volume tank 616will be different. For example, if oxygen conservation (e.g., whenoxygen accumulates when the patient is exhaling) is the primary focus, amuch larger air volume tank 616 should be sized and used in conjunctionwith proportional flow control. However, if the goal is just to output abolus of oxygen at the beginning of inspiration or end of expirationduring each breath with no proportional flow control, a much smaller airvolume tank 616 should be sized, which can further enhance portabilityof the device but reduce oxygen conservation or high flow outputcapabilities. The use of proportional flow control is especiallyrelevant for 50 PSIG high pressure gas sources, such as medical hospitaloxygen wall supplies, where a large bolus of high-pressure gas can causeover-inflating of the lungs or barotrauma.

In addition to the flow sensor 518, the ventilator 600 may include asecond flow sensor 519. Accordingly, the flow sensor 518 may be referredto as the first flow sensor or output flow sensor, and the second flowsensor 519 may be referred to as the input flow sensor. As such, theflow of the input gas IG may be measured using the second flow sensor519. The controller 504 may be programmed to maintain the input gas IGflow at a fixed oxygen conservation ratio (e.g., 3×), and the input gasIG may be accumulated in the air volume tank 616 when the proportionalcontrol valves 602, 605 are closed. The flow of the input gas IG may be,for example, 2 LPM. Hence, a 6 LPM flow of gas would be outputted fromthe air volume tank 616, and one or more of the proportional controlvalves 602, 605 would be open during the useful phase of respiration.This proportional flow control can utilize PI or PID control algorithms.The proportional gain Kp and integrator values of the PI or PID controlalgorithms may be, for example, experimentally determined and set by themanufacturer to have the smoothest and most accurate flow rate outputsat a given range. The proportional gain Kp and integrator values of thePI control may be automatically updated by the controller 504 based ondifferent input flow conditions detected by a second flow sensor 519 aswell as actual output flow detected by first flow sensor 518 vspredetermined output flow rates. The controller 504 may use feedback orfeedforward control to compensate for error and maximize flow rateprecision. The flow of the output gas OG to the user may be timecontrolled. For example, the duration of the flow of the output gas maybe set to be a variable time, thereby supplying the output gas OG withvariable volume/pressure profile based on user breathing times (e.g.,90% exhale time for start of flow and 70% of inhale time for end offlow). Alternatively, the output gas OG supplied to the user may bevolume controlled, pressure controlled, flow controlled, or acombination therein. Further, the output gas OG does not necessarilyneed to be a square waveform, but rather can consist of different flow,pressure, and/or waveform patterns, which can be dynamically adjusted bythe ventilator 600 on a breath by breath basis. Some of these waveformpatterns can include descending ramp, sinusoidal, oscillatory, stepfunctions, and/or a combination of waveforms thereof, which can also begenerated using mathematical patterns based on sensor data and lungmodels programmed into the controller 504.

In this configuration, the oxygen conservation ratio is a fixed value.Alternatively, the flow rate of the output gas OG may be controlled bythe user. In one example, the user can have a flow dial or knob thatspecifies a flow rate of the output gas OG of 4 LPM. As such, the oxygenconservation ratio would be algorithmically adjusted by a softwareprogram being run by the controller 504 based on the user input. Thisadjustment in output flow rate can be performed by the ventilator 600based on computations involving one or more sensors (e.g., the pressuresensor 526 or external sensors or devices not contained in theventilator 600). Sensors or devices that can be used to automaticallyadjust oxygen flow rate to the user include, but are not limited to,sensors or devices that measure the following, independently or incombination thereof: breathing flows, pressures, O₂ concentrations, CO₂concentrations, humidity, acoustics/voice, temperature, trace gas orliquid concentrations, pulse oximetry, vital signs such as heart rateand/or blood pressure, and/or physical movement of the ventilator 600.

The ventilator 600 may include proportional pressure control valvesinstead of proportional flow control valves 602, 605. This would beespecially useful for pressure-controlled ventilators, as well as lowpressure (i.e., less than 5 PSIG) input gas sources where the springsinside existing miniature electronically controlled proportional controlvalve designs are generally too stiff to precisely control the flow oflow pressure gas. These pressure control valves generally function asclosed-loop electronic air pressure regulators. Single and double looppressure control valve architectures generally include two or morevalves, a manifold, internal pressure transducer, and electroniccontrols (not shown). Output pressure is proportional to an electricalsignal input. Pressure is controlled by two solenoid valves. One valvefunctions as the inlet control and the other as an exhaust. The pressureoutput is measured by a pressure transducer internal to the proportionalpressure control valve system and provides a feedback signal to theelectronic controls. This feedback signal is compared against thecommand signal input. A difference between the two signals causes one ofthe solenoid valves to open allowing flow in or out of the system.Accurate pressure is maintained by controlling these two valves. Bycontrolled pressure, the flow is slowed down and hence a maximum flowrate from the air volume tank 616 can be set that is lower than the flowrate that would be output from an air volume tank 616 and standardelectronically controlled solenoid valve 502 (FIG. 5) that fully opens.With this proportional pressure control, the pressure output can beprecisely controlled to reduce the risks of barotrauma or lungoverinflation from the ventilator gas output. Flow control can also beexecuted indirectly by controlling pressure by measuring flow ratesusing the first flow sensor 518. The flow may be controlled, forexample, by varying the times of the inlet control and exhaust timingsof the valves in the proportional pressure control system.

With reference to FIG. 7A, a ventilator 700 uses one or more ultra-lowpressure gas sources. The structure and operation of the ventilator 700is substantially similar to the structure and operation of theventilator 500 (FIG. 5) described above, except for the featuresdescribed below. The ventilator 700 includes a turbine or pressurizationpump 702 in fluid communication with the tubing 503. The turbine 702adds energy to increase pressure of the output gas OG, thereby allowingthe flow restrictions to be minimized. Accordingly, the ventilator 700can use smaller tubing patient interfaces (e.g., flow outlet airline 520and breath detection airline 524). In other CPAP devices andventilators, large bore breathing tubing (e.g., 22 mm diameter tubing)is used due to the low pressure gas output, which generally ranges from4-20 cm H₂O pressure. In some cases, this air entrainment ratio canexceed 25 times the amount of volume/flow rate of the input gas flow IG.Oxygen concentrators or generation devices may be used to generateultra-low oxygen output pressures in order to minimize the energyconsumption of the gas separation process. Assuming 2 LPM oxygen gas isproduced at 0.6 PSIG output pressure and 49 LPM of air entrainment, thiswould result in a total pressure for the air-O₂ mixture of 0.024 PSIG.Based on flow coefficient calculations, this would mean only 32.35 LPMof gas with a 0.024 PSI pressure differential can flow through a 10 mmcircular patient interface orifice. Hence, if a discreet and small boretubing were to be used as the patient interface, for example with a duallumen nasal cannula or oxygen eyeglass frames with nasal pillows, eitherlower amounts of air entrainment or higher pressure oxygen gas would berequired for the patient interface to be feasible. Hence, in theventilator 700, the turbine or pressurization pump 702 is used toincrease the pressure of the input gas IG in the oxygen from an oxygenconcentrator (not shown) or gas source from an inlet 704 that is influid communication with the ventilator tubing 503. The valve 502 is influid communication with the ventilator tubing 503. The input gasflowing from inlet 704 flows through a valve 502 (e.g., a solenoidvalve) and is measured by the flow sensor 518. The input gas IG frominlet 704 flows through the air entrainment device 518, and then flowsto the turbine or pressurization pump 702. Hence, the pressure of theair-O₂ mixture is increased by adding energy into the ventilator 700.For example, if the pressure of the air-O₂ gas mixture increases from0.024 PSIG to 0.146 PSIG, then 19.7 LPM of gas can flow throughventilator tubing 503 with a 2.4 mm² orifice cross sectional area. Thiswould make, for example, a pair of discreet oxygen eyeglasses thatutilizes two separate 1.2 mm diameter by 2 mm oval air channels feasiblewith 40 LPM of flow through the patient circuit.

In some embodiments as shown in FIG. 7B, the ventilator 700 may includea PEEP valve 701, such as a mechanical or pneumatic valve. The PEEPvalve 701 is in fluid communication with the breath detection airline524.

In some embodiments as shown in FIG. 7C, the ventilator 700 nay includean internal oxygen concentrator 708, which can be fluidly connected toallow external gas sources. This internal oxygen concentrator 708 can beof several types, such as, but not limited to: pressure swingadsorption, vacuum pressure swing adsorption, ultra-rapid pressure swingadsorption, oscillator pressure swing adsorption, “molecular gate”pressure swing adsorption, thermally cycled pressure swing adsorption,thermal swing adsorption, Joule-Thomson liquefaction units for theproduction of liquid oxygen from atmospheric air, gaseous oxygen tanks,liquid oxygen tanks, membrane based gas separation units, andcombinations thereof.

With reference to FIGS. 8A and 8B, a check valve actuation system 800for ventilatory output using ultra-low-pressure gas sources isdescribed. For example, a low-pressure input oxygen or compressed airgas flow of 6 LPM may be used with exemplary gas source pressures of 0.2PSIG±0.05 PSIG. A check valve 802 with 0.3 PSIG cracking pressure and0.25-inch diameter may be selected. A pressure actuator 804 can be usedto open the check valve 802 initially by creating a minimum flow (e.g.,0.1 LPM) required to actuate the check valve 802 at the crackingpressure of 0.3 PSIG. The check valve 802 is configured to then be keptopen during the period of useful respiration through a plurality ofmethods. For example, the check valve 802 is mounted in a verticalposition such that only a pressure actuator 804 can open the check valve802. The end of the check valve 802 is capped and then the input gas IGcan flow horizontally through a valve inlet 806 and then through an opencheck valve flap 808. The flap 808 includes a first flap portion 812 anda second flap portion 814. The check valve 802 includes a sidewall 810,and the valve inlet 806 extends through the sidewall 810. Each of thefirst flap portion 812 and the second flap portion 814 is pivotallyconnected to the sidewall 810, thereby allowing the flap 808 to movebetween a closed state (FIG. 8A) to an open state (FIG. 8B). The opencheck valve flap 808 may be thick (e.g., 0.2 inches) but it has lowresistance/low cracking pressures to allow easy opening by the pressureactuator 804. The pressure actuator 804 is configured to actuate thecheck valve 802. The check valve 802 is in a vertical orientation. Uponactuation of the pressure actuator 804, the check valve 802 switchesfrom an OFF or closed state to an ON or open state. Specifically, uponactuation of the pressure actuator 804, a downward actuating pressure APis exerted on the flap 808, causing the flap 808 to move from the closedstate to the open state. When the check valve 802 is in the ON or openstate, the input gas IG can flow through the flap 808 from the tubing503 and then curve downward through a tube that connects to the outletof the check valve 802.

The pressure actuator 804 may include metal or rubber bellows, aircylinders, pneumatic pistons, servo motors, electromagnetic coils,oscillators, hydraulic actuators, air volume tanks, turbines, airblowers, and other fluid power mechanisms to pressurize a volume of gasat low or high frequency, or actuate the check valve 802. The pressureactuator 804 may include a piezoelectric micro-blower 816 that utilizesa high frequency piezoelectric oscillator that vibrates at 28 kHzfrequency such that a mean effective pressure (MEP) is created. Thisgenerated MEP may be in the form of an oscillatory pressure waveform.The latency of the mechanical response of the check valve 802 topressure changes would be slower than the electrical response of thepiezoelectric oscillators. This generated MEP may be electronicallycontrolled by turning the micro-blower 816 ON or OFF. For example, aMOSFET switch (not shown) may be used to turn the micro-blower 816 ON orOFF to increase pressure in the small chamber/volume (in the check valve802) by the user or machine. The air accumulates at the valve inlet 806of the check valve 802 just enough to exceed the cracking pressure ofthe check valve 802 during the useful phase of respiration, while alsominimizing energy consumption of the piezoelectric micro-blower 816.

When the check valve 802 is in the closed state, the edges of the flap812 prevent the flow of inlet gas IG through the check valve 802,reducing the amount of volume that needs to be pressurized to actuatethe check valve 802 using the pressure actuator 804. The check valve 802also has an air channel 818 defined on an inner valve surface 820 of thecheck valve 802. The air channel 818 can be a ring-shaped and cantherefore extend along the entire circumference of the inner valvesurface 820. Further, the air channel 818 has a convex shape. The airchannel 818 is disposed around the flap 812. When the check valve 802 isin the closed state. The flap 812 covers the valve inlet 806, therebypreventing the inlet gas IG from entering the check valve 802 throughthe valve inlet 806. When the check valve 802 is in the open state, theflap 812 no longer covers the valve inlet 806 and therefore the valveinlet 806 is open. As a consequence, the inlet gas IG can flow from theventilator tubing 503 to the check valve 802 through the valve inlet806. Then, due to the convex shape of the air channel 818 the inlet gasIG, a convex gas flow profile is created along the air channel 818. Assuch, the inlet gas IG is outputted through the check valve 802 in anunrestricted flow pattern via the valve inlet 806. The thickness of theflap 812 is equal to or greater than the diameter of the valve inlet806, allowing the flap 812 to block the valve inlet 806 when the checkvalve 802 is in the closed state.

The check valve 802 can be in a horizontal-flow-through orientation.Consequently, the pressure actuator 804 can increase the pressure in asmall section of the ventilator tubing 503 right before the check valve802 to, for example, 0.3 PSIG. In such a case, adding energy to increasethe pressure inside the ventilator tubing 503 may be beneficial to movethe inlet gas IG to exceed the cracking pressure of the check valve 802.Using ideal gas state equations such as AE=RT[(P0/P1)−1+1n(P1/P0)], andthen translating the flow rate into volume and then mass using knowndensities for air at certain temperatures, it can be calculated that 10Wh of power consumption would, causing the check valve actuation system800 to continuously increase the pressure of the inlet gas IG by 0.1PSIG. The power consumption may be reduced if the variance in pressuresfrom the inlet gas IG is significantly smaller.

The check valve 802 may be electronically controlled to have variablecracking pressures. To do so, a notch, for example, may be embedded inthe edge of the flap 808. A heating element may be used. By heating theflap 808, the edge of the flap 812 expands and is locked in by the notch(not shown), closing the check valve 802. The heating would depend onthe coefficient of thermal expansion of the material of the flap 812.

With reference to FIGS. 9A, 9B, 9C, 10A, 10B, 10C, and 10D, anelectronically controlled check valve 900 that utilizes anelectromagnetic actuator 902 is described. These can includepiezoelectric actuators, electromagnetic coils, linear motors, and servomotors. Other types of actuators can also be utilized. Someelectronically controlled solenoid valves have small orifice sizes dueto the fact that generally a shaft or pin needs to be accelerated by anelectromagnetic coil, which creates limitations and tradeoffs related topower consumption, response times, and orifice diameter. For example, a0.5-inch diameter orifice electromagnetic solenoid valve would require alarge coil and high-power consumption to accelerate the shaft or pinsuch that response times are <100 milliseconds. Some passive checkvalves do not consume any power and have large orifices, such as 0.5inch in small form factors, and cannot be electronically controlled. Theelectronically controlled check valve 900 seeks to solve these problems.The electronically controlled check valve 900 includes a latch 904 andan electromagnetic actuator 902, such that a large orifice can beopened, for example >50%, while only having to accelerate anelectromagnetic coil/shaft a distance of <25% the length of the orificediameter. These numbers are only examples.

The check valve 902 includes one or more of the following: a check valveflap(s) 906, electromagnetic actuator(s) 902, and latch(s) 904. Theactuator 902 operates by linearly accelerating a pin or shaft 908 usingelectromagnetic forces from a coil through a latch 904 with a particularcutout pattern with tolerances such that the pin or shaft 908 willeasily slide through.

This pin or shaft 908 is generally circular in shape and is machined toinclude two rectangular notches that exceed the outer diameter of theshaft 908. Once the pin or shaft 908 enters the latch 904 in the properposition, such as after the backplate, the electromagnetic actuator 902rotates the pin or shaft 908 a quarter turn or 90 degrees to lock thecheck valve flap 906 in place in the closed position due to themechanical properties of the latch 908, similar to turning a key. Thisturning mechanism can be controlled using a separate or integrated servomotor or rotary actuator (not shown), wherein the rotational position ofthe actuator can be measured and controlled, using a hall effect sensoror other means of sensing. This latch 904 can be placed in a variety ofpositions below or above the inlet of the check valve flap 906,including but not limited to: near the center, near the edge of theflap, straight down, straight up, slanted at a positive 57 degree angle,slanted at a negative 80 degree angle, slanted at a positive 15 degreeangle. This should be mechanically designed in such a way that thetravel distance of the actuator shaft 908 is minimized. Theelectromagnetic actuator 902 may be a rotary actuator and may includecomponents, which may be micro or nanofabricated and/or machined,including but not limited to: electrostatic actuators, thermalactuators, electromagnetic rotors, and fluidic actuators. For example, asolenoid armature can be designed such that the armature can be rotatedback and forth in a linear or non-linear pattern at high cyclicalfrequency such that its position can be precisely controlled, similar tothe actuator and head mechanism found in hard disk drives or HDDs.Consequently, the latch 904 can be easily and quickly released and/orheld in place at a cyclical rate, and/or various durations of time. Itis contemplated that the electromagnetic actuator 902 may include aguide screw (not shown). As such, the electromagnetic actuator rotatesthe pin or shaft 908 linearly across a guide screw at a precise positionat high linear speed using fast rotational speeds. The rotationalposition of the pin 908 can be measured using a hall effect sensor orother means of sensing such as force or position when lightly contactingthe face of the latch 904. The direction of rotation of theelectromagnetic actuator 902 can be reversed such that the pin or shaft908 can be moved back and forth using the guide screw. The pin 908 canbe released from the latch 904 and rotate counterclockwise down theguide screw using the recoil force from a spring (not shown) that isactuated by rotating the pin 908 using the guide screw.

The pin 908 and the latch 904 may be configured as a “button locking”pin latch mechanism 907 as illustrated in FIGS. 10A, 10B, and 10C. Insuch a case, only a linear solenoid or actuator 906, and no rotary orcombo rotary and linear motion actuator, is required. The actuator 902exerts a linear force LF to accelerate a pin 908 a into a latch 904 a.As a result, the pin 908 a moves in a downward direction DW into thelatch mechanism and is clamped into place by the latch 904 a. Theactuator pin or shaft 908 may contain inside or have a spring (notshown) around the pin or shaft 908 a. As such, when the electromagneticactuator 902 (e.g., linear solenoid actuator) pushes (as is shown byarrow PHS) on the pin 908 a after clamped into place by the latch 904 a,the pin 908 a would be pulled (in the direction PLL) by the recoil forceof the spring. Only one actuator 902 may required such that a mechanicallatch 904 can hold both flaps 906 closed when the pin 908 is clampedinto the latch 904. In one embodiment, one or more mechanical latch(s)904 are proximal to the flaps 906, such that a portion or the entiretyof the pin latch mechanism 907 is embedded or comprise the flaps 906,such that the distance of linear travel between the mechanical latch(s)904 and the flaps 906 is minimized, for example less than 1 mm traveldistance.

The electronically controlled valve 900 may not just be useful forventilator or respiratory device applications, but also in applicationssuch as industrial automation. For example, some high pressurecompressed air systems can be replaced with lower pressure blower basedcompressed air systems to reduce energy consumption by >20% usingelectronically controlled check valve 900 with compact size profiles,low power requirements, and large orifice sizes.

With reference to FIGS. 11, 12, 13, and 14, a ventilator 1000 hasinvasive and non-invasive ventilation modes. The structure and operationof the ventilator 1000 is substantially similar to the ventilator 500,except for the features described below. The ventilator 1000 has acarbon dioxide (CO₂) exhalation valve 1002 inside the ventilator 1000.In some embodiments, the exhalation valve 1002 is not a component of theventilator circuit. Further, in other embodiments, this exhalation valve1002 could comprise a mechanical/pneumatic PEEP valve instead of anelectronically controlled variant, wherein the PEEP provided to thepatient could be manually adjusted by the patient by rotating the knobof the valve (not shown), which controls the spring force that creates aresistance to the patient's exhalation that once this resistance isovercome, the PEEP valve opens. In some embodiments, this PEEP valve isnormally open wherein there is an electronically controlled bypass thatopens if the main power supply is shut off while in use or fails, whichcould be powered using a miniature servo motor and the ventilator'sbackup battery (both not shown). This PEEP valve or exhalation valve1002 could exist in non-invasive or invasive ventilators, as well asventilator embodiments with one or more lumens. This ventilator 1000 canoperate in a variety of ventilatory modalities including, but notlimited to, one or more of the following: Assist Control, SIMV, PressureControl Ventilation, Volume Control Ventilation, Volume Assist orAugmented Ventilation, Proportional Assist Ventilation, Bioimpedancecontrolled ventilation, High Frequency Ventilation, and/or NeutrallyAdjusted Ventilatory Assist.

The Assist Control ventilation mode may be especially useful and/oroptimized for acute respiratory distress syndrome (ARDS) and/or COVID-19ventilator patients, and/or for patients with Stage III-IV chronicobstructive pulmonary disease (COPD). In the present disclosure, controlbreaths are defined as machine breath output over a fixed period oftime. For example, a machine breath will be output every 6 seconds whenpatient spontaneous inspiration cannot be detected, and, hence, thepatient is non-spontaneous breathing when control breaths are outputsince the ventilator 1000 is breathing for the person. The controlbreath settings are controllable by the user or machine, with tidalvolume output controlled by the valve 502, and, in certain embodiments,a calculated fixed value based on input flow. Other settings that can becontrolled include inhalation to exhalation ratios, for example. Eachcontrol tidal volume output can have the same or varying duration. Fixedtidal volume values can be programmed into the controller 504 as textbased numeric values based on input flow rate of the input gas IGrounded to nearest 0.1 LPM for example. Assist breaths are defined asspontaneous breaths detected and triggered between control breaths usingnasal pharynx pressure sensor breath detection software. O₂ orcompressed air flow rate of the input gas IG is controlled by the useror machine between, for example 0-200 LPM, which is measured by the flowsensor 518. Gas sources include but are not limited to: blower airflowcontroller, wall oxygen supply in hospital, oxygen concentrator, and/orair compressor such that ventilator tidal volume setting adjustments aredone either automatically by the machine using the firmware/software ofthe controller 506 or physically by the user using a knob, switch,touchscreen, and/or any other human-computer interface. A squarewaveform fixed tidal volume output can be generated at a preset volumebased on O₂ flow rate input detected by the flow sensor 518. However, adescending ramp, ascending ramp, sinusoidal, and/or other orcombinations of waveforms thereof can be generated by the ventilator1000 as the tidal volume output. Assist breath tidal volume can be thesame or different compared to control breath tidal volume. With autovolume control, the ventilator tidal volume output may be a fixed valuebased on input compressed air or O₂ flow that begins being output at forexample 90% exhale time to provide low level PEEP or during start ofinhalation to provide IPAP.

A low tidal volume low peak inspiratory flow (PIF) ventilation may beused as a lung protective strategy for ARDS. While other PIFs of 180 LPMcan generate high peak inspiratory pressures and cause barotrauma incertain ventilated patient populations, the ventilator 1000 generatesbetween 150 mL to 750 mL tidal volumes. However, ventilators with higheror lower tidal volume output settings can be created. An inspiratoryhold time is created by closing both the CO₂ exhalation valve 1002 andthe tidal volume output valve 502 to generate a plateau pressure thatcan be measured and improve oxygenation/gas exchange in lungs, whichgenerally lasts 30% of the tidal volume delivery time. This inspiratoryhold timing can be adjustable or non-adjustable by the user orautomatically by the machine by adjusting valve timing characteristicsusing the controller 506. Other variables that can be adjusted by thecontroller 506 or human-computer interface to modify ventilator functioninclude, but are not limited to: PEEP, IPAP pressures, inspiratorytiming, inspiratory flow rates, expiratory flow rates, expiratorytiming, and/or FiO₂%. The PEEP may be algorithmically adjusted by theventilator 1000 based on breath detection software time control. Thebreath detection software can generate PEEP predicted by pressure sensor526 measurements by outputting tidal volume during last 10.0% ofexhalation for example.

The ventilator 1000 can include a display interface (not shown) fordisplaying one or more parameters to a user. In one example, a simpleLCD screen (not shown) configured as a display interface, may be used.As such, the ventilator 1000 may be configured as a “plug and play”device, not requiring connection to a monitor or other separate userinterface. In such case, the flow rate of the input gas IG may beadjusted by the user, for example, in response to the informationdisplayed to the user via the display interface. The ventilator 1000 mayinclude a peak airway pressure sensor 1006 in fluid communication withthe pressure sensor 526. The LCD screen may indicate, using a graphic orLED bar, when adjustments to gas source input flow should be made basedon peak airway pressure sensor measurements measured by the peak airwaypressure sensor 1006. Generally, gas source flow input should beincreased when SpO₂ saturation is less than 90%, which can be measuredusing a separate patient/vital signs monitor and/or pulse oximeter anddecreased when peak airway pressure is high (i.e., more than 35 cm H₂O).A fixed tidal volume delivered per breath can be provided to a user viathe LCD screen or via a separate instruction manual based on adjustmentof hospital wall O₂ supply flow rates. The user may increase tidalvolumes delivered to a patient by increasing O₂ flow rate input at inlet704. The inlet 704 may be an input gas source connector and may includeinclude a barb fitting, DISS connectors, quick connectors, and others.For example, the input gas source connector may be a ¼″ NPT barb fittingthat connects to a 50-psi hospital wall pipeline O₂ supply or O₂ tankusing ¼″ ID oxygen tubing. The inlet 704, the flow outlet airline 520,the breath detection airline 524, and an CO₂ exhalation conduit 1004 mayinclude tubing connectors. For example, inlet 704, the flow outletairline 520, breath detection airline 524, and an CO₂ exhalation conduit1004 may include quick change connectors such that modifications to thepatient circuit and/or gas source can be made, allowing components to bereplaced. CO₂ exhalation conduit 1004 is in direct fluid communicationwith the CO₂ exhalation valve 1002 and is configured to receiveexhalation gases from the user. The ventilator 1000 includes the airentrainment device 522, which in some configurations is a fixed FiO₂based on mechanical design and hence should be easy to remove andreplace in order for a user to adjust FiO₂.

Sensors, such as the pressure sensor 526 for measuring breathingcharacteristics and/or other aspects of patient physiology, may beeither internal to the ventilator 1000 or external to ventilator 1000and connected to patient interfaces, such as breathing flow sensors.

Examples of low tidal volume low PIF ventilation settings include, butare not limited to, as follows: 1) 5 LPM output flow rate, 150 ml tidalvolume, 1.8 second tidal volume delivery duration; and 2) 40 LPM outputflow rate, 750 mL tidal volume, 1.125 second tidal volume deliveryduration

The patient monitoring LCD number text display may include, but is notlimited to, the following variables: tidal volume being delivered (mL),breathing frequency (BPM), I:E ratio, peak airway pressure (cm H₂O),PEEP (cm H₂O), gas source/O₂ flow rate input (LPM)

Control breathing can be output at a fixed time period, such as onceevery 6 seconds, for non-spontaneous breathing patients during that timeperiod and can be used in a critical or non-critical care setting underthe supervision of a trained physician for patients with ventilatoryimpairment. The ventilator 1000 can be used in adult, pediatric, and/orneonatal patient populations. The ventilator 1000 can also be used inhomecare, hospital, ambulatory, and/or transport applications dependingon configuration. With regard to detecting spontaneous breathing,exhalation is detected using breath detection software, which takesnasopharynx pressure sensor data measured from the breath detectionairline 524 and uses mathematical formulas to predict whether a patientis going to transition from an exhalation to inhalation, which allowsfor the use of a pressure sensor significantly more sensitive thanrequired in the ISO 80601-2-79 guidance. In one example, the pressuresensor may be up to six times (6×) more sensitive than required in theISO 80601-2-79 guidance. This allows for PEEP of less than 5 cm H₂O tobe provided by the ventilator 1000 automatically, rather than relying onfixed pressure triggers as in many predicate devices, which sometimesfail.

Peak airway pressure is monitored using a peak airway pressure sensor1006, with alarm conditions that trigger by the alarm 508 if certainpressure levels are reached such as 45 cmH₂O. Lung protective strategieswith regard to patients with ARDS and this Assist Control ventilationare described. These include the use of low peak inspiratory flows andadjustable tidal volumes based on O₂ flow into the ventilator 1000, withindictors to the healthcare provider via the LCD display provided (notshown). This ventilation strategy is designed to support the patientwork of breathing while minimizing the risk of high peak airwaypressures that can cause ventilator-associated lung injury (VALI) orhypoventilation, while also promoting oxygenation by providingsupplemental oxygen with a fixed 100% FiO₂ setting or same as gas sourceinput to the patient and eliminating CO₂ from the patient circuit everysingle breath with no leakage and little resistance. In someembodiments, the FiO₂ can also be adjusted or variable, either by themachine or user, by adding the air entrainment device 522, representedby FIGS. 1-4 and described in the specification.

The audible safety alarm 508 in the ventilator 1000 is designed formedical applications for use in ventilation equipment, certified thatthis audible safety alarm is recognized under the IEC 60601-1-8standard. This alarm 508 is a component of the electronics board 506that may include a specially designed speaker-housing assembly with nocircuitry. Other alarm types can also be utilized including but notlimited to: piezoelectric type speakers, audio amplifiers, and/orelectromagnetic speakers. With this alarm 508, the OEM only needs toinput a simple square wave signal with one frequency component, and theother needed harmonic sound frequencies are generated acoustically. Thisgreatly simplifies implementation of an audible alarm sound in an IEC60601-1-8 since the harmonic peaks are designed to be acoustically equalto the sound level required under IEC 60601-1-8. This alarm relies onthe 2nd option for compliance, a melody table listed in Annex F of theIEC 60601-1-8 standard where specific medical conditions/applicationsare assigned individual melodies. These melodies are essentially littletunes that change in pitch per the tables in Annex F. The objective isthat the medical personnel using medical equipment with alarms that usethese melodies will become familiar with them which can help the medicalpersonnel respond more quickly and more appropriately when a specificmelody alarm sounds. This ventilator 1000 utilizes the alarm 508 togenerate high, medium, or low priority warning sounds depending on thecondition of the patient or malfunctions with ventilator equipment suchas tubing disconnects. The audible sound has fundamental frequency <1000Hz, with at least 4 harmonic frequencies within ±15 dB of thefundamental frequency. This alarm 508 has specific waveform and timingrequirements for the three priority sounds, which includes a sound risetime specified by the alarm manufacturer. Alarm settings can include,but are not limited to, the following: if O₂ input from inlet 704 flows,but no breathing/exhalation is detected within 6 seconds, soundalarm—low priority; if the electrical power source 510 is beingused—medium priority; if O₂ is connected in the wrong conduit (e.g.,breath detection airline 524, flow outlet airline 520, or a CO₂exhalation conduit 1004), sound alarm—high priority; if the pressuremeasured during inspiration using peak airway sensor 1006 is less than40 cmH2O for more than 3 breaths in a row, sound alarm—high priority; ifthe CO₂ exhalation conduit 1004 gets disconnected from ventilator 1000within 6 seconds of assist or control breath output, sound alarm—mediumpriority; if the flow outlet airline 520 gets disconnected fromventilator 1000 within 6 seconds of assist or control breath, soundalarm—high priority.

CO₂ rebreathing is minimized in accordance to the ISO 80601-2-79standard through the use of a novel ultra-low resistance and leak freepatient circuit shown in FIG. 11 that utilizes an active valve controlinside the ventilator 1000. Unlike other ventilators, no exhalation orinhalation valves are components of the patient circuit, but rather allcontrol for inhalation and exhalation is performed inside the ventilator1000. This is done using separate flow outlet airline 520 (i.e., aninspiration airlines) and CO₂ exhalation conduit 1004. The CO₂exhalation conduit 1004 utilizes the CO₂ exhalation valve 1002, whichmay be: a solenoid valve with >6.5 mm orifice, a pinch valve that opensand closes 7 mm diameter tubing, and/or an electronically controlledcheck valve described in FIGS. 8-9, among others. This CO₂ exhalationvalve 1002 allows for near zero resistance breathing since it is asimilar diameter as a 6.5 mm endotracheal tube during invasiveventilation or intubation. Patient expired gas flows back throughbacteria/viral filter 1008, which includes a 22 mm breathing tubeconnector to minimize exhalation resistance, before coming into contactwith any internal device components. This viral/bacterial filter canfeature standard coaxial ISO connectors (ISO 5356-1) that connect tostandard breathing tubes using 15 mm ID/22 mm OD connectors forapplications in breathing circuits, scavenging circuits, mechanicalventilation, and manual ventilation, including bag valve mask (BVM).This viral/bacterial filter 1008 is designed for single-patient use and,in some embodiments, can have bidirectional airline, be in-line, lowflow resistance of 1.5 cm H₂O pressure at 60 LPM, hydrophobic andelectrostatic filtering properties, dead space of 45 mL, andultrasonically welded. An HME filter or active heated humidificationsystem and/or airline can be added to the flow outlet airline 520 toheat and moisturize the output gas OG output to the patient in order toprevent drying of airways and promote patient health/comfort. Patientgas is expelled to the atmosphere after bacteria/viral filtering throughCO₂ exhalation valve 1002 and then an exhaust muffler 1010 that is influid communication with the CO₂ exhalation valve 1002. Other safetyfeatures related to exhalation are also implemented. One of which isthat for example, the CO₂ exhalation valve 1002 is a normally openvalve, which would allow the user to exhale even if the devicemalfunctions.

This ventilator 1000 utilizes an AC-DC converter (not shown), which is a20 W high density and small size AC/DC module type medical grade powersupply. It can operate between 80-264 VAC, has a low no load powerconsumption less than 0.075 W, and a high efficiency up to 87%. ThisAC-DC converter has Class II double insulation, high lifespanattributable to the interior potting, 5G anti-vibration, high EMCperformance, 4KVAC isolation, etc. The AC-DC converter is designed bythe manufacturer to meet IEC60601-1 and ANSI/AAMI ES60601-1 standards.

AAA Nickel Metal Hydride (NiMH) Rechargeable Batteries and an 8-batteryholder may comprise the electrical power source 510. This iselectrically designed to be a 12V circuit as a battery backup in case ofmain power supply failure, which makes the power electronics on theelectronics board 506 simpler. The electrical power source 506 may berecharged after use by AC power module operation when the main powersupply is back online. Each AAA cell is 1.2V with a rated capacity of800 mAH. These alkaline batteries are safe and effective, used inmillions of electronics devices across the world for over a decade. Thebattery cells may follow ANSI-1.2H1 and IEC-HR03 standards.

The ventilator 1000 may utilize an AC Power Module 1012 known as theSeries DD12: IEC Appliance Inlet C14 with Filter, Fuseholder 1- or2-pole, Line Switch 2-pole. Technical characteristics of this powermodule include: <5 μA (250 V/60 Hz) of current leakage, >1.7 kVDCbetween L-N and >2.7 kVDC between L/N-PE dielectric strength, front sideIP40 protection according to IEC 60529, 1 or 2 pole fuseholder,Shocksafe category PC2 according to IEC 60127-6 for fuse-links 5×20 mm.The fuse drawer meets requirements of medical standard IEC/EN 60601-1.Further, this power module also includes a high frequency line filter asrequired under IEC 60601-1 as well as EMI filtering and Class X1- andY1-capacitors. A line switch and power switch under Rocker switch2-pole, non-illuminated, in accordance to IEC 61058-1 is also included.This power module 1012 is ideal for applications with high transientloads and electrical safety. The manufacturer of this power module hasalso stated that the aluminum case of the power module provides good EMIshielding, that all single elements are already wired, and that thispower module is suitable for use in medical equipment according toIEC/UL 60601-1. A power receptacle 1014 connects to the AC power moduleto deliver wall power from a 120V or 240V source, depending on countryof origin and/or use. The device utilizes a power receptacle or US PowerSupply Cord with IEC Connector C13 with a V-Lock. This power cord israted for 125 VAC, 50/60 Hz. This product is designed by themanufacturer to meet the following standards: IEC 60320-1, IEC 60320-3,UL 498, CSA C22.2 No. 42, IEC 60950-1.

With reference to FIG. 15, a ventilator 1100 is similar to theventilator 1000 shown in FIG. 11. However, one major difference is thatthere is no CO₂ exhalation valve in this configuration. For invasiveventilation in the configuration shown in FIG. 15, a single limbventilator circuit would be required. This type of configuration wouldbe more suited for ventilators with a focus on non-invasive homeventilation, where the capability of optional but less frequent useinvasive ventilation is desired. This configuration without the activeCO₂ exhalation valve inside the ventilator 1100 substantially reducespower consumption and weight compared to the ventilator 1000 shown inFIG. 11, allowing for lightweight portability with battery power.

With reference to FIG. 16, a non-invasive ventilator circuit 1200includes a breathing tubing 1202 (e.g., 22 mm tubing), an adapter 1204,an oxygen tubing 1206, and a patient interface 1208. This breathingtubing 1202 and any other tubing described herein can have variousconnector and inner tubing diameter sizes not specified in thisdisclosure. The inlet of the breathing tubing 1202 connects to thebreath detection airline 524 to minimize flow resistance and measurebreathing pressures (e.g., nasopharynx pressures) accurately withoutsignal interference from the oxygen flow. The oxygen tubing 1206 wouldconnect at the inlet of the tidal volume output airline flow outletairline 520. The tidal volume from the ventilator 1100 would be outputto the patient in a unidirectional flow from the inlet of the oxygentubing 1206 to the barb inlet of the adapter 1204, and then to thepatient interface 1208 either during a control or assist breath. Theadapter 1204 is meant to serve as a connection point for the oxygentubing 1206 and the breathing tubing 1202, allowing tidal volume flowoutput to the patient interface 1208 as well as bidirectional breathdetection software data measurements using the 22 mm breathing tubing1202 as a flow conduit to the sensors inside the ventilator, such as anasopharynx pressure sensor 526 with a pressure measurement range of±0.018 PSIG.

With reference to FIG. 17, an invasive ventilator circuit 1300 for theventilator 1000 disclosed in FIG. 10 is described. This invasiveventilator circuit 1300 includes a breathing tubing 1302 (e.g., 22 mmtubing), adapter(s) 1304, 1306, oxygen tubing 1308, breath detectiontubing 1310, and a patient interface 1312. This breathing detectiontubing 1310 and any other tubing described herein can have variousconnector and inner tubing diameter sizes not specified in thisdisclosure. The inlet of the breathing detection tubing 1310 connects tothe CO₂ exhalation conduit 1004 and/or viral/bacterial filter 1008 tominimize flow resistance during exhalation, which is actively controlledby the ventilator. The oxygen tubing 1308 is configured to be connectedat the inlet of the flow outlet airline 520. The tidal volume from theventilator 1000 would be output to the patient in a unidirectional flowfrom the inlet of the oxygen tubing 1308 to the barb inlet of theadapter 1304, and then to the patient interface 1312 either during acontrol or assist breath. The bidirectional breath detection softwaredata measurements are taken using the breath detection tubing 1310. Thebreath detection tubing 1312 is connected to adapter 1306. As such, thebreath detection tubing 1320 functions as a flow conduit to the sensors(e.g., pressure sensor 526 and peak airway pressure sensor 1006) insidethe ventilator 1000. The adapter connector(s) 1304, 1306 can be separateor combined into one adapter. These adapter(s) peak airway pressuresensor 1006 serve as a connection point for the oxygen tubing 1308, 22mm breathing tubing 1302, and breath detection tubing 1310. Theseadapter(s) 1304, 1306 allow tidal volume flow output to the patientinterface 1312 as well as bidirectional breath detection software datameasurements and active exhalation control without any sensor signalinterference from different simultaneously occurring gas flows, such asbreathing flows and/or tidal volume output from the ventilator 1000.

With reference to FIG. 18, a ventilator 1400 includes an internal oxygenconcentrator 1402, which can be fluidly connected to allow external gassources. This internal oxygen concentrator 1402 can be of several types,such as, but is not limited to: pressure swing adsorption, vacuumpressure swing adsorption, ultra-rapid pressure swing adsorption,oscillator pressure swing adsorption, “molecular gate” pressure swingadsorption, thermally cycled pressure swing adsorption, thermal swingadsorption, Joule-Thomson liquefaction units for the production ofliquid oxygen from atmospheric air, gaseous oxygen tanks, liquid oxygentanks, membrane based gas separation units, and combinations thereof. Ina non-limiting example, the internal oxygen concentrator 1402 can beconfigured as disclosed in U.S. patent application Ser. No. 16/704,413,to which the current disclosure claims priority to, and benefit of, andwhich is hereby incorporated by reference in its entirety

Several of these internal oxygen concentrators 1402 utilize an internalair compressor or blower unit (not shown). The ventilator 1400 mayinclude inlet 704, which may function as an inlet source for gas source.This gas source may additionally include compressed air flow from anexternal blower or compressor fed to an internal air compressor orblower unit. The internal air compressor may be used to increase thepressure of the inlet gas IG, which, either due to the higher flowsand/or pressures, can potentially increase the potential oxygenproduction flow rate of the internal oxygen concentrator 1402. Thisinlet 704 may be in fluid communication with a check valve 1404 to allowthe inlet gas IG to be stored in an air volume tank 616. The air volumetank 616 may be external and/or internal to the ventilator 1400. Thecompressed air (i.e., input gas IG) may be fed directly to the gasseparation media such as an adsorbent column. Further, in otherembodiments, inlet compressed air can be used to drive a rotor thatgenerates electrical energy to operate the system and/or recharge thebatteries in addition or separately from AC wall outlet electricity. Theventilator 1400 may therefore be pneumatically and/or electricallypowered. This can potentially be used to allow the internal oxygenconcentrator 1402 to switch between a portable mode, wherein oxygen flowrates of around 5 LPM max are expected, and a stationary mode, whereoxygen flow rates of 15 LPM or more can be produced.

The internal oxygen concentrator 1402 can be configured to detect whencompressed air or other gas mixture is fed into the ventilator 1400. Inresponse to detecting that the compressed air or other gas mixture isfed into the ventilator 1400, the ventilator 1400 shuts off or reducesthe power usage of the internal air compressor, reducing energyconsumption of the ventilator 1400 significantly during in-home use.When the oxygen concentrator 1402 is not producing 100% duty cyclecontinuous flow oxygen output, the air volume tank 616 may be used tostore compressed air from either the internal air compressor or externalair supply. When oxygen, for example, is not being produced usingexternal compressed air from the inlet gas source, the compressed aircan be used to create a Venturi vacuum using a Venturi vacuum generator(not shown) that improves the gas separation performance and/or allowsfor suctioning the patient using the ventilator 1400. The internaloxygen concentrator 1402 may produce continuous or intermittent flows ofoxygen that do not synchronize with the user's breathing. To do so forexample, the air volume tank 616 may be used to accumulate producedoxygen. This air volume tank 616 may also be used for sensormeasurements, such as for measuring oxygen concentration puritypercentage and/or flow rates of the O₂ output without using a flowsensor, such as the first flow sensor 518 and/or the second flow sensor519. In some cases, one or more of the proportional valves 602, 605 areplaced upstream of the air volume tank 616 to, for example, implement PIand/or PID flow control of the oxygen gas output. The air entrainmentdevice 522 is used to augment the oxygen output with additionalentrained room air, potentially reducing oxygen requirements for theuser without requiring the use of an additional and/or separate airblower or compressor for air-O₂ mixing as done in other ventilators. Theventilator 1400 may include a separate outlet gas supply airline 1406such that additional oxygen and/or compressed air can be fed into theventilator 1400 from an external gas source, including but not limitedto: oxygen tanks, portable oxygen concentrators, stationary oxygenconcentrators, liquid oxygen tanks, air compressors, and/or air blowers.This separate outlet gas supply airline 1406 can be configured such thatthe gas accumulates in the air volume tank 616. Then, the air from theair volume tank 616 is received by the air entrainment device 522 and/oris controlled passively for output to the patient by check valve 1408 oractively by electronically controlled valve 502. This output of gas tothe user is controllable by breath detection of spontaneous breathingusing the breath detection airline 524 and, for example, the pressuresensor 526, and/or via ventilator machine settings such as controlbreaths for non-spontaneous breathing patients.

With reference to FIG. 19, a vacuum pressure swing adsorption (VPSA)system 1500 includes a plurality of valves for on demand or intermittentoxygen production. These valves could include but are not limited to thefollowing valve types: check valves, electronically controlled solenoidvalves, rotary valves, electronically controlled check valves, andvalvular conduits such as Tesla valves. In some embodiments, a valvelessPSA system could be created such that motor control allows the change ingeneral pressure/flow directions from pressurization to depressurizationflow through the modulation of power using a control method such as PWM,such that the motor control is implemented with one or more DC motorpowered pumps and/or blowers, in some cases at high cyclical frequencysuch as 10 kHz. In some oxygen concentrators, pressure swing adsorption(PSA) is used to separate nitrogen from air using a zeolite adsorbentcolumn in order to produce an enriched oxygen gas flow. This nitrogenmust be desorbed from the adsorbent column at a cyclic frequency byreducing the pressure in the system to exploit the physical adsorptionproperties of the zeolite material, such as the adsorption isotherm andmass transfer coefficients. High pressure air compressors that producein a range of between 1.5 to 2.5 atmospheres of pressurization may beused in other PSA systems to create the driving pressures required inother oxygen concentrator systems, because high pressure swing ratiosare needed for several reasons. One primary reason is the fact thatactive valve control using electronic solenoid valves in other PSAsystems has a high energy consumption, creates flow restrictions at lowpressure, and inhibits high cyclic frequencies. With the use of highpressure swing ratios, longer adsorbent columns, which can also becharacterized as adsorbent columns with length to diameter, or L:Dratios, greater than one, are generally used in order to preventnitrogen breakthrough that generally occurs in shorter adsorbent columnsystems, which substantially reduces oxygen output purity. Also, withmore zeolite material, the adsorption process can be run for longerbefore regeneration of the adsorbent column is required. Governing thisphenomenon is nitrogen uptake kinetics or mass transfer. Adsorptionkinetics is theorized to be highly logarithmic due to the electrostaticproperties in the active Li+ ion sites in the zeolite crystallinestructure, which can allow us to draw comparisons to parallel platecapacitors where charge accumulates much faster in the beginning.Generally, thinner zeolite laminates and smaller zeolite particle sizesincrease the rate of mass transfer. Isotherm is also a physicalcharacterization of adsorption. Isotherm represents the amount of gasadsorbed by zeolite at a fixed temperature as pressure increases.Further, to maintain high oxygen output purity and reduce the risk ofadsorbent fluidization/nitrogen breakthrough, lower pressure ratios thanother PSA systems can be utilized. This also means that in order tominimize the amount of zeolite adsorbent required to separate out acertain amount of gas, a high cycle time frequency should be used. Asshown, Type I isotherms (such as those in the separation of N₂), aregenerally somewhat logarithmic in nature, with it being theorized thatincreases or decreases in pressure closer to absolute vacuum producelarger changes in adsorption quantities per unit pressure due to theIdeal Adsorbed Solution Theory (IAST) and the heat of adsorption.

With continued reference to FIG. 19, a PSA or VPSA system that usespressure swing ratios less than 1.5 are used. An ultra-rapid VPSA systemmay be used and may include thin zeolite laminates instead of packedpellet beds in order to increase the rate of mass transfer, allowingfaster cycle times and smaller PSA system, and reduce the pressure dropacross adsorbent.

With continued reference to FIG. 19 the VPSA system 1500 is a passivevalve pressure-controlled system designed to eliminate the use of activevalve control that would create flow restrictions and inhibit highcyclic frequency rates. This gas separation method employed by the VPSAsystem 1500 is used to separate out nitrogen from air using a zeoliteadsorbent column to produce enriched oxygen gas flow. In the VPSA system1500, the cycle times are based on the electronic control of the ON/OFFswitching frequencies of the blowers (MOSFETs may potentially be used),allowing for much higher cycle times than previous PSA architectures.Low cracking pressure check valves are used to control the direction ofgas flows. The VPSA system 1500 includes a blower or air compressor 1502and it functions by turning ON the blower or air compressor 1502 whenoxygen output is desired. The ON/OFF timing of the blower 1502 can bedetermined via different methods including but not limited to: fixedcycle time frequency programmed into the blower motor controller orsystem microcontroller; breath detection during the useful phase ofpatient respiration, which can be variable in duration and/or duringportion(s) of inspiration or expiration; variable cycle time frequencybased on flow output characteristics demanded by machine settings oruser breathing patterns. Cycle times for turning the blower 1502 ON/OFFcan range between 2000 Hz to 10 seconds, and can depend on the latencyof the power electronics inside the blower such as DC motors,pressurization/flow profiles of the blower output, and/or adsorbentcolumn dimensions, mass transfer kinetics, and/or combinations thereofin order to optimize system performance for power density of oxygenproduction flow, energy efficiency of oxygen production flow, and/orflow rate of output desired. The VPSA system 1500 further includes a lowcracking pressure check valve 1504 in fluid communication with theblower 1502 through the ventilator tubing 503. When the blower 1502 isON, the pressurized air PA from blower 1502 flows through ventilatortubing 503 to the low cracking pressure check valve 1504. The VPSAsystem 1500 further includes an adsorbent column 1506 in fluidcommunication with the low cracking pressure check valve 1504. Theadsorbent 1506 is downstream with the low cracking pressure check valve1504. After flowing through the low cracking pressure check valve 1504,the pressured air PA flows to the adsorbent column 1506. The adsorbentcolumn 1506 contains a zeolite adsorbent and desiccant. Duringadsorption as shown in FIG. 19, when the pressurized air flows throughthe adsorbent column 1506, the nitrogen from the pressurized air isadsorbed. The VPSA system 1500 includes a second check valve 1508downstream of the adsorbent column 1506. Enriched oxygen gas EO existingthe adsorbent column 1506 then flows to the second check valve 1508. Thesecond check valve 1508 has a cracking pressure based on the pressuredrop across the adsorbent column 1506 and hence outlet gas flowpressure.

The VPSA system 1500 further includes a vacuum blower 1512 in fluidcommunication with the adsorbent column 1506. During desorption as shownin FIG. 20, the vacuum blower 1512 can be operated at variable ON/OFFcycle timing based on the same conditions as the pressurization blower1502 or different conditions. Further, there can be overlap between theblowers ON/OFF cycles. In addition, the VPSA system 1500 also includes avacuum check valve 1510 in fluid communication with the vacuum blower1512. The pressurization blower 1502 will turn OFF, and then the vacuumblower 1512 will turn ON. As such, the vacuum check valve 1510 will OPENto allow the nitrogen N to flow from the inlet of the adsorbent column1506 to the vacuum blower 1512. The nitrogen N in the vacuum blower 1512is then vented to the atmosphere or can be used for other purposes. Whenthe vacuum blower 1510 is ON, the cracking pressure of the vacuum checkvalve 1510 would allow the vacuum check valve 1510 to be opened by thevacuum blower 1512, but at the same time only be able to be actuated bythe vacuum blower 1512. The pressure from the pressurization blower 1502at the inlet of the adsorbent column 1506 cannot open the vacuum checkvalve 1510. This vacuum check valve 1510 and the vacuum blower 1512airline can be placed in a variety of different positions and/or usingconnectors, including but not limited to: T-connector, inlet or outlettubing of adsorbent column 1506, separate adsorbent column 1506connector at inlet, outlet, and/or other position in or around adsorbentcolumn 1506 that is separate from other gas airlines. The second checkvalve 1508 and/or the other check valves 1504, 1508, 1510 may be a Teslavalve(s) such that there is no cracking pressure but rather flow ismostly unidirectional based on the flow resistance of the Tesla valve ina backflow scenario. The check valves 1504, 1510, 1512 may beelectronically controlled check valves disclosed in FIGS. 8-9. Thepressure output of the blower 1512 can be as low as 1 kPa with acracking pressure of the check valve 1504 being as low as 0.9 kPa, withthe cracking pressure of the check valve 1504 determined by themanufacturer of the VPSA system 1500 based on the flow rate and pressurespecifications of the vacuum blower 1512. The blower(s) 1502, 1512 mayalso be electronically controlled using pulse-width modulation (PWM).Accordingly, the pulse widths of oxygen output during adsorption anddesorption of nitrogen can be variable and optimized for certain flowrate output profiles, with different settings based on energy efficiencyvs “power density” (oxygen production flow/lb weight of system)considerations. Further, the flow and pressure profiles of the blowers1510, 1512 may be electronically varied per cycle by adjusting the motorspeed in accordance with performance data. The blowers 1502, 1512 canhave different pressure and/or flow profiles ranging in pressure from−30 to 30 kPa. Moreover, at least on of the blowers 1502, 1512 mayoperate with 100% duty cycle. As such, the VSPA system 1500 may includetwo separate inlet and two separate outlet airlines that are configuredso that the blower can function as a dual pressure and vacuum pump,which can be electronically controlled in terms of switching functionsbetween vacuum and pressure, flow rates, pressure, ON/OFF duty cycles,and/or other variables. The pulses of oxygen at less than 1 Hz frequencycan be created by the VPSA system 1500.

A fast response flow sensor, such as the flow sensor 518, can bereplaced with an air volume tank. In such a case, a pressure sensor (notshown) is used to measure how long it takes the take to get filled andthen calculates based on the blower ON/OFF times (e.g., what ispercentage duty cycle of the oxygen production) to then determine theoutput flow rate from the internal oxygen concentrator. Further, oxygenconcentration-percentage purity sensors generally have a very slow(e.g., less than 4 seconds) response time and would not be able todetect the purity of a fast O₂ pulse (e.g., less than 100 ms). The flowsensor 518 can be used to measure how long it takes to fill an airvolume tank to determine the O₂ flow rate and can also be used to allowO₂ to accumulate in the tank and measure O₂ purity percentage datareadings. An ultra-fast response optical oxygen sensor or massspectroscopy system can be created to measure the purity of each oxygenpulse.

FIGS. 21 and 22 illustrate a novel zeolite laminate adsorbent structure1600 and a system 1700 for making the same. The goal of this work is tocreate zeolite adsorbents that facilitate ultra-rapid pressure swingadsorption processes, and a PSA architecture that facilitatesultra-rapid cycle times and maximizes adsorbent productivity. This thinzeolite laminate may be manufactured using graphite dies and sinteringof zeolite powder. Under high heat and pressure, it has beenexperimentally determined that zeolite pellets grounded into powder(with for example 0.2-50-micron particle sizes) can be formed intolaminates under high pressure using a hydraulic press, for example 12tons to produce 100 MPa compression, and 2000 degree C. temperatureswithout the use of binders that reduce adsorption performance, such askaolin clay, by reducing the available surface area of the zeolite inthe sintered structure. Different pressures and temperatures forcreating the laminate can be used other than those stated above. Thisheating process can be in the form of rapid induction heating. Thisheating process binds the edges of zeolite compressed powder body to the‘melted metal’ that comprises the adsorbent column 1506, which is thencooled and allows a bonded airtight seal around the zeolite laminate inaddition to the press fit of the compressed powder body. Other materialscan also be utilized for the adsorbent column including but not limitedto: metals, thermoplastics, ceramics, and/or composite materials such asfiberglass reinforced plastics. Binders, such as kaolin clay, can beutilized. Ammonium bicarbonate or other pore former compounds can beintroduced to add porosity to the compressed powder body, which can beremoved during the heating process at 100 degrees C. in a vacuum-oven orother post-processing. This zeolite laminate can be manufactured as acompressed ‘green body’, which means that a mass of zeolite powder iscompressed at high pressure and not heated. This ‘green body’fabrication process is to maximize porosity, which sintering tends toreduce. The zeolite laminate can be directly molded inside a tube ormechanical structure that comprises the adsorbent column 1506, such thatthe zeolite laminate is never demolded. This reduces a concern found inexperiments, where the zeolite laminate can collapse during demolding.In the fabrication of the zeolite laminate or porous body, techniquesfrom ceramic sintering and powder metallurgy can also be utilized. Tomaximize the lifecycle of the N₂ adsorption zeolite, a desiccant filter(or desiccant material) 1701 should be placed before pressurized airencounters this N₂ zeolite. Water vapor and CO₂ substantially reduce thelifecycle of the N₂ adsorbent zeolite, which results in other adsorbentcolumns needing to be replaced.

The desiccant material 1701 can be in a variety of mechanical formfactors including but not limited to pellet, filter, and/or laminateform. Generally, these N₂ zeolites generally include, but is not limitedto, Lithium exchanged 5A or low silica X type zeolite. The desiccantmaterial 1701 generally includes, but is not limited to: silica gel,activated alumina, and/or sodium based 5A zeolite. Two differentmaterial laminates can be in the adsorbent column 1506, one desiccantlaminate and an N₂ adsorbent laminate. A single laminate can be created.For example, a bottom layer of the laminate may be placed at the inletof the laminate and is a desiccant, and the middle/top layer of thelaminate may be placed at the outlet of the laminate and is the N₂zeolite adsorbent. The lifecycle of the zeolite adsorbent column 1506may be increased by placing a desiccant laminate at the inlet distal endof the adsorbent column 1506 and placing an air gap between the N₂adsorbent laminate, which is placed at the outlet end of the adsorbentcolumn 1506. This air gap can also include a diffusion plate to slowdown the gas travel. The goal of this air gap (with or without thediffusion plate) is to minimize the diffusivity of water vapor and CO₂that decreases the lifecycle of the N₂ adsorbent material 1702. Further,the use of vacuum 1704 can also assist with removing water vapor and CO₂at the inlet end of the N₂ adsorbent material 1702.

A separate airline 1706 can be added at the inlet distal end of theadsorbent column 1506 exclusively for water vapor/CO₂ removal from thedesiccant material with the second vacuum airline being at the inlet endof the N₂ adsorbent zeolite laminate, which may be near the outletdistal end of the adsorbent column 1506. The water vapor/CO₂ removalfrom the desiccant laminate 1701 using a vacuum purge and N₂ removalfrom the N₂ adsorbent laminate using a vacuum purge can be separatedusing a check valve 1708 in combination with or exclusive of separatedairlines. A long purge vacuum cycle can be used (for example 10 minuteevery 24 hours when VPSA system 1500 is not being used by a patient) toregenerate the adsorbent bed and remove as much water vapor/CO₂ aspossible. This can also be a manual process by the user and instructedby the durable medical equipment (DME) or ventilator provider. This longpurge vacuum cycle can also be used for the N₂ adsorbent column 1506 tomaximize lifecycle. A heating and/or cooling element (not shown) canalso be added to assist with this adsorbent column lifecyclemaximization process by removing water vapor/CO₂ and/or N₂ through along vacuum and/or heat purge process. This use of heating and coolingelements during the adsorption and desorption phases with smalladsorbent columns can improve performance of the VPSA process and isknown as thermally cycled PSA. The system 1700 can include additionalcheck valves 1708 to control the flow in the circuit.

With reference to FIG. 23, a ventilator 1800 can function as a manuallycontrolled and/or automated suctioning device. Suctioning is used toremove airway secretions commonly found in cystic fibrosis patients, aswell as other patient populations that may or may not requireventilation. In many cases, invasively ventilated patients produceadditional mucus since the trach tube bypasses the upper airway, whichnaturally warms and humidifies breathing air. In ventilated patients,this can necessitate periodic mucus removal from the tracheostomy tubeto ensure proper breathing. Also, secretions left in the tube can becomecontaminated and a chest infection can develop. This suctioninggenerally takes place at vacuum pressures between 10-150 mmHg, dependingon the patient and clinical application. Some hospitals use acentralized vacuum system that can be connected to a pressure regulatorand then to the patient via a color-coded airline. Portable suctioningunits also exist; however, these portable suctioning units generallyoperate at lower pressures such as 10-15 mmHg and/or use separate vacuumpumps or medical aspirators that are not integrated with a ventilatorysupport device. The ventilator 1800 may also be used as an airwayclearance device such as a mechanical insufflation-exsufflation device,also known as cough assist. A mechanical insufflation-exsufflationdevice is designed to noninvasively clear secretions from the lungs bysimulating a natural cough. Like a normal deep breath, this type ofdevice applies positive air pressure (insufflation) to obtain a largevolume of air within the lungs. The device then quickly reverses theflow of air by shifting to negative air pressure (exsufflation). Theresulting high expiratory flow at vacuum pressures helps removesecretions out of the airway just like how a deep natural cough would.

The ventilator 1800 includes an inlet 1802 configured to receivecompressed air or oxygen supply and a Venturi vacuum generator 1804 influid communication with the inlet. As such, the compressed air oroxygen supply from the inlet 1802 can flow to the Venturi vacuumgenerator 1804. In the ventilator 1800, the compressed air or oxygensupply is not being output as a tidal volume to the patient orinsufflation, this compressed air or oxygen supply can be used to createa vacuum or exsufflation using the Venturi vacuum generator 1804 usingthe same gas source, similar to that disclosed in FIG. 4. The ventilator1800 further includes a viral/bacterial filter 1806 in fluidcommunication with the the Venturi vacuum generator 1804. The secretionsS can flow through the viral/bacterial filter 1806 and exhausted througha nozzle 1808. The nozzle 1808 is downstream of the Venturi vacuumgenerator 1804. The viral/bacteria filter 1806 can be disposed in anexhalation airline 1810 that is connected to the Venturi vacuumgenerator 1804. The exhalation airline 1810 with viral/bacterial filter1806 can be removed and a disposable tank for secretions (not shown) canreplace the nozzle 1808. The Venturi vacuum generator 1804 may beuser-replaceable using push-quick tubing connectors such that it can bereplaced or sanitized by user and/or medical personnel on a periodicbasis. A fluidic device or pump can be added to theexhalation/exsufflation airline 1810 to remove the secretions S. Theexhalation/exsufflation airline 1810 may be separate from the normalexhalation airline described previously. Alternatively, the secretions Scan be pumped out of the Venturi vacuum generator 1804 using fluid suchas a liquid cleaning solvent periodically, for example once after everyuse and prevent clogging during repeated use. This compressed air oroxygen supply can be internal to the ventilator 1800 via an air bloweror internal oxygen concentrator. Alternatively, the compressed air oroxygen supply may be an external gas supply, such as a 50 psi aircompressor, compressed air supply in the hospital, a wall oxygen supply,an external oxygen concentrator, and/or an external oxygen tank orcombination of internal/external gas sources hereof.

The Venturi Vacuum generator 1804 may be mechanically designed such thata lower pressure high flow input gas pressure source can be used togenerate a higher pressure “deep” vacuum with lower flow. The vacuumpressure, flow rate, and ramp settings for insufflation and/orexsufflation can be adjusted by the user or machine based on a varietyof factors including, but not limited to: device settings such as coughassist (non-invasive) or general suctioning (invasive), duration ofsuctioning therapy, triggering sensitivity or phase of breathing timingfor insufflation and/or exsufflation, and/or pressure/flow rampwaveforms. An active valve control circuit can be used such that thecompressed air/O₂ from inlet 1802 or an internal gas source is output asa tidal volume to a patient via a valve 1816 and aninhalation/insufflation airline 1814, which in some instances canconnect to a hose barb or 22 mm breathing tubing. The valve 1816 and theinhalation/insufflation airline 1814 are in fluid communication with theinlet 1802.

Further, the insufflation airline 1814 and the exsufflation airline 1810can also be connected to the same single limb ventilator circuit using awye connector (not shown). This compressed air/02 can then be routed tothe patient during insufflation or as a tidal volume to the Venturivacuum generator 1804 using an electronically controlled valve 1816. TheVenturi vacuum generator 1804 would then create a vacuum or exsufflationthat would flow through the exhalation airline 1810, based on the inputcompressed gas source supplied to the Venturi vacuum generator 1804. Inthe Venturi vacuum generator 1804, the compressed inlet gas plus vacuumgenerated and any resulting secretions would be extracted and then beexhausted out the nozzle 1808. The flow and/or pressure input from thecompressed gas source can be controlled by the ventilator 1800 itself.For example, an internal O₂ concentrator can adjust motor speed tochange output oxygen flow rate and pressures, which would affect thevacuum pressures and flows generated based on the mechanical design ofthe Venturi vacuum generator 1804. In other instances, the pressure andflow ramp profiles for exsufflation can be controlled (not by the inputgas source) but rather using the valve 1816. The valve 1816 may be anelectronically controlled proportional flow and/or pressure controlvalve. An air volume tank (not shown) and/or additional flow/pressuresensors can also be added to allow more precise control of theseexsufflation flow/pressure characteristics. The electronicallycontrolled proportional control valve 1816 can be replaced with a manualball valve wherein a user can use a knob on the exterior of the deviceor human-computer interface such as touchscreen to create an orificerestriction that would slow down the flow of gas, decreasing the flowrate and hence the pressure/flow profiles of the exsufflation. This allcan also apply to the control of insufflation to the user. Anelectronically or manually set valve at the vacuum inlet of the Venturivacuum generator 1804 can be set such that the vacuum pressures and/orflow rates resulting from the inlet compressed air/O₂ from the valve1816 can be adjusted manually by the user or automatically adjusted bythe ventilator 1800. The Venturi vacuum generator 1800 can be used incombination with or substituted with a vacuum blower (not shown), suchthat the vacuum blower can be electrically controlled to turn ON duringexsufflation, and OFF during insufflation. This ON/OFF switching, insome embodiments, can be controlled using MOSFET switch(s) or othermeans of electronic control.

With reference to FIG. 24, a Mechanical Oscillator pressure swingadsorption (PSA) and High Frequency Ventilation system 1900 isdescribed. The goal of oscillatory PSA system 1900 is to allow the useof ultra-rapid cycle times with minimal flow resistance, therebyreducing fluid pressure requirements and eliminating the need for checkvalves or active valve control. Instead, the valve control or evenelectronic ON/OFF control of blowers are replaced with motion control ofactuator(s) 1902, which can include but are not limited to:electromagnetic solenoids, linear motors, DC motors with gear mechanismsto convert rotary motion into linear motion, piezoelectric actuators,hydraulic actuators, pistons, servo motors, and/or air cylinders. Inaddition to the actuators 1902, the ventilator 1900 includes an actuatorshaft 1904 coupled to the actuator 1902 and an oscillator shaft 1906coupled to the actuator shaft 1904. The oscillator shaft 1906 can beaccelerated via the forces exerted by the actuator 1902 via the actuatorshaft 1904. A short push-pull stroke and high frequency actuations canbe used to create high frequency oscillations. The actuator 1904 can becombined with an air spring 1908 or actual spring, such that a recoilforce can be mechanically generated once the oscillator shaft 1906travels a certain distance. This distance can be controlled mechanicallybased on the dimensions of the spring housing 1910 and/or the springcoil 1912. The air spring 1908 can be eliminated by using electronicposition and/or motion control of the actuator 1902. For example, aprecision feedback closed loop algorithm(s), such as PID control, can beimplemented such that the acceleration of the actuator shaft 1904 can bemeasured and allow for precision position control (with for example 0.1mm positioning accuracy) compared to predictions. This can allow for theimplementation of an oscillatory PSA system 1900 such that two or moreopposing actuators can be actuated in a pulsating manner such that thesystem operates at resonance frequency. This can be optimized usingelectronic control such that oxygen performance is maximized, and noiseof the system is minimized. Accelerations and decelerations of theactuator shaft 1904 can also be variable, such that the actuator shaft1904 can accelerate faster than it would decelerate, varying the timesof adsorption and desorption, which can be controlled using for examplePWM. The oscillator shaft 1906 can be coupled to ball bearing(s) 1911,such that less force is required to accelerate and decelerate theoscillator shaft 1906. A piston 1913 can be mechanically designed, suchthat fluid can flow through the piston 1913 in a certain geometricpattern. The fluid can be inputted or exhausted via certain ports/airchannels that comprise the piston 1913. The piston 1913 can bemanufactured using a variety of manufacturing methods including, but notlimited to: 3D printed, machined, molded, cast, and/or fabricated as oneor more assembled components using one or more materials including butnot limited aluminum, titanium, stainless steel, thermoplastic,composites, and/or polymeric materials.

The PSA system 1900 can also be designed such that piston 1913 uses airseals instead of lubricants, such that loose tolerances would berequired to create pressurization/depressurization cycles such that itis mainly dependent on the geometric design of the piston 1913. Pumpassemblies and additional pistons in series or in parallel can beoperated to amplify pressure, flow, and/or frequency of the overallsystem. The piston 1913 can be attached and/or a component of theoscillator shaft 1906, such that the piston 1913 oscillates at the samespeed and direction as the oscillator shaft 1906. An air blower or airfan 1914 can be included in the PSA system 1900 to drive air into theair intake port(s) 1916. The location and size of the intake port(s)1916 and exhaust port(s) 1918 are based upon the mechanical design ofthe enclosure 1920. The air blower or air fan 1914 can be microscale,nanoscale, ducted, and/or heat exchanged.

In the position shown in FIG. 24 low pressure or ambient air from theair fan 1914 flows through the intake port(s) 1916 and one or more airchannels that comprise the oscillator piston 1913. One or more airchannels that comprises the piston 1913 allows gas flow to a layer ofzeolite adsorbent 1922. In this position, the oscillator piston 1913compresses an amount of this gas, separating out nitrogen from theintake air. The oscillator shaft 1906 then moves in the oppositedirection. As a result, the volume between the oscillator piston 1913and the layer of zeolite 1922 expands, reducing the pressure in thesystem while simultaneously the piston 1913 travels such that thenitrogen gas can be released from the zeolite via exhaust port(s) 1918.The oscillator piston 1913 can comprise two halves wherein the airchannel(s) and exhaust port shape(s) are in perpendicular and/oropposite directions from each other. The enclosure 1920 contains asecond layer of N2 or zeolite adsorbent 1922, such that two separateadsorption and desorption cycles occur each back and forth pistonstroke. This overall oscillatory PSA system 1900 can facilitate the useof ultra-low pressures, such as less than 1 cmH2O pressure, as well asultra-fast cycle times (for example more than 1000 Hz) using precisionmachining, additive manufacturing, microfabrication techniques, and/or acombination of technologies thereof. This oscillatory PSA system 1900can be used to generate oxygen as an internal oxygen concentrator and/oras a gas source for a ventilator with different ventilation modesincluding but not limited to: Assist Control, Volume Control, PressureControl, SIMV, Volume Assist, PAV, and/or high frequency ventilation.The oscillatory PSA system 1900 is used as a high frequency ventilator,such that tidal volume or O₂ output is produced at a high frequency,such as more than 10 Hz. A mean effective pressure (MEP) is generated bythe oscillatory PSA system 1900. The MEP can also be measured and/orcontrolled using, for example, varying the pulse widths and/or peakairway pressure sensor measurements. This can be used in combinationwith or separate from an air entrainment device 522. Further, the heatengine of the PSA system 1900 can be designed that the PSA cycleoperates similar to reciprocating and/or linear heat engine designs,wherein the combustion process with fuel injection/ignition would bereplaced with zeolite adsorbent(s) and mechanical energy is inputinstead of created. Examples of PSA heat engine architecture designsinclude the diesel cycle, Wankel cycle, free linear pistons, Otto cycle,and/or jet turbines. Energy input sources can include electric motors,hydraulic actuators, planetary gears, other mechanisms of convertingmotion, and/or heat engines that combust fuels such as hydrocarbons,alcohol, and/or biofuels. Further, the oscillator piston 1913 can createmotion including but not limited to the following motion patterns:sinusoidal, toroidal, rectilinear, rotational, and/or wave patterns.

With reference to FIGS. 25A and 25B, a piezoelectric oscillator PSA andhigh frequency ventilation system 2000 is described. The piezoelectricoscillatory PSA system includes piezoelectric microblowers 2002, whichare surface mounted to a printed circuit board 2004. The piezoelectricmicroblowers 2002 include a piezoelectric oscillator element 2006 thatvibrates at, for example 28 kHz, and an integrated check valve (notshown). When the piezoelectric oscillator 2006 oscillates back andforth, a unidirectional pressure/flow is produced. The vibrations ofthis piezoelectric oscillator 2006 can be electronically controlled suchthat the pressures, flows, and oscillatory frequency can be varied basedon electrical response to changes in voltage and/or power. PWM can beused to control the frequency of the piezoelectric oscillator 2006, suchthat the oscillator 2006 can be accelerated and decelerated at differentor the same speeds. Each individual piezoelectric microblower 2002 canbe controlled individually or as a group of two or more blowersoperating in series and/or parallel. The piezoelectric microblowers 2002can be mounted in an enclosure, such that with two microblowers 2002,for example, the pressure output can be doubled for example from 2 kPato 4 kPa, while keeping flow the same as one microblower. Further,electronic control can be used such that full depressurization andpressurization cycles can be achieved. For example, MOSFET switches (notshown) can be used to turn the blower(s) 2002 ON or OFF. As such, themicroblowers 2002 can be electronically controlled such that theoscillator element 2006 will not turn OFF mid-oscillation when vibratingat high frequency such as 28 kHz, but rather will wait to turn OFF untilthe end of an individual oscillation. One or more microblowers 2002 canbe used for pressurization during the adsorption cycle while a separateset of reverse microblower(s) 2002 can be used to produce vacuum duringthe desorption cycle. Alternatively, the piezoelectric oscillators 2006can be used to replace or in combination with the piezoelectricmicroblowers 2002. The piezoelectric oscillators 2006 can be used toproduce high frequency pressurization and vacuum, moving very smallamounts of gas per oscillation. Electromagnetic or other types ofoscillators can also be used.

With reference to FIG. 25A, the piezoelectric oscillator PSA system 2000functions by turning ON a set of pressurization microblowers 2002, whichpressurize an air chamber 2008. This compressed air then flows through azeolite adsorbent 2010, which can be a variety of mechanical structuresincluding but not limited to pellets, laminates, microfabricated thinfilms, and/or porous honeycombs. The nitrogen from the pressurized airis adsorbed by the zeolite, producing an enriched oxygen flow that flowsout a valve 2012. The valve 2012 may be passively controlled such as acheck valve, actively controlled using electronics such as a solenoidvalve, and/or a combination thereof.

With reference to FIG. 25B the desorption cycle then occurs. Thus, thepressurization microblowers 2002 are then turned OFF, and the vacuummicroblowers 2014 are turned ON. As a consequence, the nitrogen isremoved from the zeolite adsorbent 2010 and vented to the atmosphere.

This adsorption and desorption process can be performed at a highcyclical rate, in some cases in excess of 14 kHz. There can be overlapbetween these two phases such that the sets of pressurizationmicroblowers 2002 and vacuum microblowers 2014 can both be OFF or ON atthe same time. Only one set of microblowers 2002 can be used. Forexample, air blowers, external and/or internal, can be used to drive airinto the PSA such that only a set of vacuum microblowers 2002 is used,making the system a vacuum swing adsorption or VSA cycle. Only a set ofpressurization microblowers 2002 and no vacuum microblowers 2014 wouldbe used, such that the system 2000 is a true PSA architecture. In such acase, atmospheric or oxygen purge would be used to remove nitrogen fromthe zeolite adsorbent 2010 during the desorption phase. These pressuresand/or flows from the microblowers 2002, 2014 for pressurization anddepressurization can also be similar or different values. A Tesla valvecan be used as the valve type for valve 2012, such that a certainpercentage of the oxygen from an air volume tank (not shown) can berecirculated during the purge process in the desorption phase. Thispercentage of oxygen recirculation is variable based on the mechanicaldesign of the Tesla valve and backflow resistance.

FIG. 26 illustrates a ventilator 2100 that can function as a bilevelpositive airway pressure (BiPAP) device or continuous positive airwaypressure (CPAP) device, oxygen (O₂) concentrator, and/or ventilator 2100with different modes. The ventilator 2100 includes an enclosure 528, atubing 503 configured to receive the input gas IG, and an internaloxygen concentrator 2102 in fluid communication with the tubing 503. Thetubing 503 is entirely or at least partially disposed inside theenclosure 528 to minimize the space occupied by the ventilator 2100. Theinternal oxygen concentrator 2102 is integrated with the ventilator 2100and is therefore entirely disposed inside the enclosure 528 to minimizethe space occupied by the ventilator 2100. The internal oxygenconcentrator 2102 can be used to generate enriched oxygen flow to thepatient (i.e., output gas OG). The internal oxygen concentrator 2102 canbe turned ON or OFF either automatically using electronic control fromthe controller 504 (e.g., a microcontroller unit) or via user adjustmentof a human-computer interface, including, but not limited to, knobs,touchscreens, and/or switches. The internal oxygen concentrator 2102 canproduce and/or deliver oxygen on demand based on a patient's breathingneeds, provide a continuous flow of oxygen, and/or produce anoscillatory or irregular oxygen output pattern to the user via the flowoutlet airline 520.

The ventilator 2100 may include air entrainment device 522 in fluidcommunication with the internal oxygen concentrator 2102. The enrichedoxygen exiting from the oxygen concentrator 2102 may be be used toentrain room air using the air entrainment device 522. The ventilator2100 may additionally include an air blower 2104 in fluid communicationwith the internal oxygen concentrator 2102. The air blower 2104 may bein communication with the controller 504. The controller 504 can beprogrammed to adjust the output gas OG to the patient by the air blower2104. The air entrainment device 522 could be substituted for or used toperform air-O₂ mixing. In some embodiments, oxygen could be delivered tothe patient during useful phases of respiration as measured using thebreath detection airline 524 and the pressure sensor 526. After oxygenis delivered during the useful phase of respiration, a PEEP could beprovided using the air blower 2104 to prevent lung collapse in patientswith chronic lung diseases, especially those who are mechanicallyventilated. This output pressure from the air blower 2104 may becontrolled using the controller 504 or via user input from ahuman-computer interface 2406 (FIG. 27B), at specific ranges for example0.1-20 cmH₂O pressure. The output flow (e.g., output gas OG) may also becontrolled using the controller 504. For example, the controller 504 maycontrol the output gas OG by controlling the blower motor speed of theair blower 2104, voltage, and/or power consumption of the ventilator2100. In some embodiments, an additional pressure sensor can be added tothe outlet airline 520 to measure the output pressure of the output gasOG to the patient.

In some embodiments, the pressure of the output gas OG provided to thepatient may be controlled by the controller 504 or the user. The airblower 2104 may control the output airflow (e.g., output gas) tomodulate the pressure based on a setpoint. For example, if the outputpressure of the O₂ and/or compressed air tidal volume from the airline520 is 6.8 cmH₂O at a flow of 40 LPM and the setpoint is 3.9 cmH₂O, theair blower 2104 can output 1 cmH₂O pressure at 40 LPM flow to achievethe setpoint. In some embodiments of the invention, oxygen pulses couldbe output intermittently at a frequency greater than an inhalationfrequency. In some embodiments, during a period of useful respirationone or more pulse(s) of oxygen could be output followed in terms oftiming by one or more pulse(s) of air from the air blower 2104. Thelengths of these oxygen and/or blower air pulses can be different or thesame as each other.

In another embodiment, the air blower 2104 may be used as an integratedor separate BiPAP/CPAP machine, wherein modes and settings could beselectable, deactivated, and/or activated by the user, healthcareprovider, and/or DME based on payment/billing code. For example, the DMEsupplier may remotely, using software only, enable the ventilator 2100for use as a non-invasive ventilator if the patient were only prescribeda non-invasive ventilator. If a patient, however, requires supplementaloxygen one year later, the DME can remotely enable this feature usingsoftware and then subsequently bill Medicare or an insurance providerfor that add-on. In some embodiments, this can also include integratedoxygen and CPAP for obstructive sleep apnea patients with overlapsyndrome.

In some embodiments, the blower pressure of the air blower 2104,including IPAP and PEEP, can be controlled by the user, clinician,and/or healthcare provide, with the settings recommended or based on thepatient prescription and/or real time physiological characteristics suchas breathing, pulse oximetry data, vital signs data, etc. For BiPAP,this generally means that the pressures of the air output can rangebetween 5-20 cmH2O IPAP, and at least 3 cmH2O less for PEEP, for example2-17 cmH2O PEEP. These IPAP and PEEP variables may be independently orjointly controlled, by the machine software itself, clinician, and/oruser. For CPAP or IPAP, the pressure for IPAP and PEEP would be thesame. Hence, only one pressure setpoint would be set. In one embodiment,tidal volume and flow rates of the air blower 2104 could also becontrolled by the controller 504 (e.g., microprocessor) of theventilator 2100, a clinician, and/or the user to maximize user comfort,with guidelines based on the patient interface used which could varyfrom user to a user based on patient physiology and mask leakage. ThisPEEP could also be determined based on peak airway pressure or predictedusing the breath detection software. In some embodiments of theinvention, the ventilator 2100 can also include wireless communicationtechnology and/or features that allow the ventilator 2100 to function asan at-home sleep test, and/or at-home oxygen test, and provide patientmonitoring for the clinician.

With reference to FIG. 27, a ventilator 2200 can utilize Pulse DoseOxygen Concentrators 2204 as the input O₂ source. Other ventilators canonly use high pressure tanks or continuous flow stationary O₂concentrators as pressure sources. This limits the mobility of theseother homecare ventilators. In the present disclosure, the ventilator2200 includes a pressure actuator 2202 that can simulate user breathingto trigger a POC oxygen concentrator 2204. During operation, thepressure actuator 2202 creates a flow ramp that would start at 0 and gopast the trigger sensitivity of the O₂ conserver device, which may havea −0.20 cmH₂O pressure trigger sensitivity. This flow ramp can beoptimized based on experimental testing by the manufacturer on differentPOCs. Hence, a light vacuum force can be generated in order to triggerthe O₂ conserver. This would be done at a periodic rate, such as 15breaths or trigger cycles per minute. This periodic rate can be adjustedautomatically by the controller 504 of the ventilator 2200 and/or theuser via a human-computer interface to avoid the O₂ demanded to exceedO₂ produced. In some embodiments, the O₂ boluses from the POC canaccumulate inside an air or oxygen volume tank 516. The oxygen can bestored until delivery to the patient through the valve 602. In someembodiments, these O₂ boluses can be measured by internal flow sensor(s)and pressure sensor(s) before accumulation into the air or oxygen volumetank 516. As such, the rate of cycling of the pressure actuator 2202 canbe electronically controlled and optimized by the controller 504 basedon performance of the POC input at certain breath triggering rates.

With reference to FIGS. 27A and 27B, a ventilator 2400 is configured toswitch between the O₂ concentrator 2102 and compressed air usinginternal O₂ concentrator blower 2402 and ball valve/gear mechanism 2404.In some patient cases, medical oxygen is only required in certainsituations, such as during exertion or physical exercise, whereasnon-invasive ventilation (NIV) or a CPAP device could be required inother situations, such as nighttime sleep, where medical O₂ may not berequired. In this ventilator 2400, the blower 2402 is not utilized 100%of the time, and the ventilator 2400 can benefit from providing PEEP tothe user with the same air compressor or blower 2402 as the internaloxygen concentrator 2102. However, the air compressor or blower 2402 canbe intermittently operated with higher loading than a 100% duty due tothe characteristics of the blower electric motor, which can also allowfor the implementing of motor cooling systems that could furtherincrease the performance of the blower(s) 2402 during intermittentloading. Hence, the ventilator 2400 allows switching between medicaloxygen and compressed air. The ventilator 2400 includes a human-machineinterface 2406 (e.g., a knob) to allow the user to manually switch theventilator 2400 between the O₂ concentrator 2102 and compressed airusing internal O₂ concentrator blower 2402 and ball valve/gear mechanism2404. Alternatively or additionally, the ventilator 2400 can beautomatically switched between the O₂ concentrator 2102 and compressedair using internal O₂ concentrator blower 2402 and ball valve/gearmechanism 2404 using a miniature electric motor (not shown). Theventilator 2400 further includes a first or middle gear 2408 coupled tothe human-machine interface 2406. Activating the human-machine interface2406 (e.g., rotating the knob) causes the first gear 2408 to rotate in afirst rotational direction (such as the first rotation direction FRD1).The ventilator 2400 further includes a second gear 2410 meshed with thefirst gear 2408. Rotating the first gear 2408 in, for example, the firstrotational direction FRD1 causes the second gear 2410 to rotate in anopposite direction (for example, the second rotational direction SRD2).The ventilator 2400 further includes a third gear 2412 meshed with thefirst gear 2408. As a consequence, rotating the first gear 2408 in, forexample, the first rotational direction FRD1 causes the third gear 2412to rotate in the same direction (e.g., the first rotational directionFRD1).

The ventilator 2400 includes a first ball valve 2414 coupled to thesecond gear 2410 and a second valve 2416 coupled to the third gear 2412.As such, rotating the second gear 2410 causes the first ball valve 2414to rotate to open and close, and rotating the third gear 2412 causes thesecond ball valve 2416 to rotate to open and close. The first ball valve2414 and the second ball valve 2416 each have an open and closedposition and an orifice sized to allow high flow low pressure gas.During operation, rotating the first gear 2408 in, for example the firstrotational direction FRD1, causes the first ball valve 2414 to openwhile simultaneously causing the second ball valve 2416 to close. Also,rotating the first gear 2408 in the opposite direction (e.g., secondrotational direction SRD2) can cause the second ball valve 2416 to openwhile simultaneously causing the first ball valve 2414 to close.Alternatively, rotating the third gear 2412 causes the second ball gear2416 to open while simultaneously the rotation of the second gear 3410(in the opposite direction) causes the first ball valve 2414 to open.The opening and closing times of the first ball valve 2414 and thesecond ball valve 2416 can be controlled using the gear ratios of thefirst gear 2408, the second gear 2410, and the third gear 24162. Forexample, the first ball valve 2414 and the second ball valve 2416 mayopen and close at the same rate. It is contemplated that one ball valve(e.g., first ball valve 2414) can always be closed, while the other one(e.g., second ball valve 2416) is open. Partial opening and closing ofthe first and second ball valves 2414, 2416 is also possible. As such,the ball valves (e.g., first and/or second ball valves 2414, 2416) canalso be used as an orifice restriction to reduce flow rates into theinternal oxygen concentrator 2102 and/or air entrainment device 522.Other types of valves could also be used including, but not limited to,gate valves, needle valves, spindle valves, check valves, and/or othertypes of valves not listed.

As shown in FIG. 27B, the tubing 503 of the ventilator 2400 includes abifurcation 2418 that splits the tubing 503 into a first branch 2420 anda second branch 2422. The bifurcation 2418 is downstream of the blower2402. The oxygen concentrator 2102 is in fluid communication with thefirst branch 2420 but not with the second branch 2422. The second branch2422 bypasses the oxygen concentrator 2102. The first ball valve 2414 isdisposed in the first branch 2420, and the second ball valve 2416 isdisposed in the second branch 2422. The direction of the blower airflowcan be controlled using these first and second ball valves 2414, 2416.For example, the ventilator 2400 can be switched to use the O₂concentrator 2102 by activating the human-machine interface 2406 (e.g.,rotating the knob in the first rotational direction FRD1). Suchactivating causes the first ball valve 2414 to open, while at the sametime, causing the second ball valve 2416 to close. As a result, the theairflow originating from the blower 2402 flows through the oxygenconcentrator 2102 and into the patient. Alternatively, the human-machineinterface 2406 can be activated to close the first ball valve 2414 andopen the second ball valve 2416, causing the flow originating from theblower 2402 to bypass the oxygen concentration. As a result, the patientis provided with compressed air.

As used herein, a system, apparatus, structure, article, element,component, or hardware “configured to” perform a specified function isindeed capable of performing the specified function without anyalteration, rather than merely having potential to perform the specifiedfunction after further modification. In other words, the system,apparatus, structure, article, element, component, or hardware“configured to” perform a specified function is specifically selected,created, implemented, utilized, programmed, and/or designed for thepurpose of performing the specified function. As used herein,“configured to” denotes existing characteristics of a system, apparatus,structure, article, element, component, or hardware that enable thesystem, apparatus, structure, article, element, component, or hardwareto perform the specified function without further modification. Forpurposes of this disclosure, a system, apparatus, structure, article,element, component, or hardware described as being “configured to”perform a particular function may additionally or alternatively bedescribed as being “adapted to” and/or as being “operative to” performthat function.

The illustrations of the embodiments described herein are intended toprovide a general understanding of the structure of the variousembodiments. The illustrations are not intended to serve as a completedescription of all of the elements and features of apparatus and systemsthat utilize the structures or methods described herein. Many otherembodiments may be apparent to those of skill in the art upon reviewingthe disclosure. Other embodiments may be utilized and derived from thedisclosure, such that structural and logical substitutions and changesmay be made without departing from the scope of the disclosure.Accordingly, the disclosure and the figures are to be regarded asillustrative rather than restrictive.

What is claimed is:
 1. A ventilator, comprising: an enclosure; a tubingconfigured to receive an input gas; a flow outlet airline in fluidcommunication with the tubing, wherein the flow outlet airline includesan airline outlet, and the flow outlet airline is configured to supplyan output gas to a user via the airline outlet; a breath detectionairline including an airline inlet, wherein the airline inlet isseparated from the airline outlet of the flow outlet airline, and thebreath detection airline is configured to receive breathing gas from theuser during exhalation by the user via the airline inlet; a pressuresensor in direct fluid communication with the breath detection airline,wherein the pressure sensor is configured to measure breathing pressurefrom the user, and the pressure sensor is configured to generate sensordata indicative of breathing by the user; and a controller in electroniccommunication with the pressure sensor, wherein the controller isprogrammed to detect the breathing by the user based on the sensor datareceived from the pressure sensor; an internal oxygen concentrator influid communication with the tubing; wherein the tubing, the flow outletairline, the breath detection airline, and the pressure sensor are eachat least partially disposed inside the enclosure; and wherein theinternal oxygen concentrator is entirely disposed inside the enclosure.2. The ventilator of claim 1, further comprising an air blower in fluidcommunication with the flow outlet airline, wherein the air blower is incommunication with the controller, and the controller is configured tocontrol the air blower to control a pressure of the output gas suppliedto the user of the ventilator.
 3. The ventilator of claim 1, furthercomprising a flow sensor coupled to the tubing to measure a flow insidethe tubing, wherein the flow sensor is in communication with thecontroller, and the controller is programmed to adjust a flow of theoutput gas based on data received from the flow sensor.
 4. Theventilator of claim 1, further comprising an air entrainment device influid communication with the tubing, wherein the air entrainment deviceis configured to entrain the input gas flowing through the tubing. 5.The ventilator of claim 1, further comprising a pressure actuator influid communication with the tubing, wherein the pressure actuator isconfigured to simulate breathing by the user to trigger a pulse doseoxygen concentrator that is in fluid communication with the tubing. 6.The ventilator of claim 5, further comprising a valve in fluidcommunication with the tubing, wherein the valve is configured tocontrol a flow through the tubing, and the valve is downstream of thepressure actuator to control the output gas provided to the user.
 7. Theventilator of claim 1, further comprising a blower in fluidcommunication with the tubing, wherein the blower is configured to forcethe output gas to the user, the tubing includes a bifurcation downstreamof the blower, the bifurcation splits the tubing into a first branch anda second branch, the oxygen concentrator is in fluid communication withthe first branch, the second branch bypasses the oxygen concentrator. 8.The ventilator of claim 7, further comprising a first ball valve and asecond ball valve, wherein the first ball valve is disposed in the firstbranch to control a fluid flow through the first branch, the second ballvalve is disposed in the second branch to control a gas flow through thesecond branch.
 9. The ventilator of claim 8, further comprising ahuman-machine interface to control the first ball valve and the secondball valve.
 10. The ventilator of claim 9, further comprising a firstgear, a second gear, and a third gear, wherein the first gear is coupledto the human-machine interface such that activating the human-machineinterface causes the first gear to rotate, the first gear is meshed withthe second gear such that rotation of the first gear in a firstrotational direction causes the second gear to rotate in an opposite,second rotational direction.
 11. The ventilator of claim 10, wherein thethird gear is meshed with the first gear such that rotation of the firstgear in the first rotational direction causes the third gear to rotatein the first rotational direction.
 12. The ventilator of claim 11,wherein the third gear is coupled to the second ball valve such thatrotation of the second gear in the second rotational direction causesthe first ball valve to close.
 13. The ventilator of claim 12, whereinthe third gear is coupled to the second ball valve such that rotation ofthe third gear in the first rotational direction causes the second ballvalve to open.
 14. The ventilator of claim 13, wherein each of the firstball valve and the second ball valve has an open position and a closedposition, and the input gas bypasses the oxygen concentrator when thefirst ball valve is in the closed position and the second ball valve isin the second position.
 15. The ventilator of claim 14, wherein theinput gas flows through the oxygen concentrator when the first ballvalve is in the open position and the second ball valve is in the closedposition.
 16. A ventilator, comprising: an enclosure; a tubingconfigured to receive an input gas; a flow outlet airline in fluidcommunication with the tubing, wherein the flow outlet airline includesan airline outlet, and the flow outlet airline is configured to supplyan output gas to a user via the airline outlet; a breath detectionairline including an airline inlet, wherein the airline inlet isseparated from the airline outlet of the flow outline airline, and thebreath detection airline is configured to receive breathing gas from theuser during exhalation by the user via the airline inlet; a pressuresensor in direct fluid communication with the breath detection airline,wherein the pressure sensor is configured to measure breathing pressurefrom the user, and the pressure sensor is configured to generate sensordata indicative of breathing by the user; and a controller in electroniccommunication with the pressure sensor, wherein the controller isprogrammed to detect the breathing by the user based on the sensor datareceived from the pressure sensor; an internal oxygen concentrator influid communication with the tubing; and wherein the oxygen concentratoris entirely disposed inside the enclosure.
 17. The ventilator of claim16, wherein the pressure sensor is entirely disposed inside theenclosure.
 18. The ventilator of claim 17, further comprising a blowerin fluid communication with the tubing, wherein the blower is configuredto force the output gas to the user, the tubing includes a bifurcationdownstream of the blower, the bifurcation splits the tubing into a firstbranch and the second branch, the oxygen concentrator is in fluidcommunication with the first branch, the second branch bypasses theoxygen concentrator.
 19. The ventilator of claim 18, further comprisinga first ball valve and a second ball valve, wherein the first ball valveis disposed in the first branch to control a fluid flow through thefirst branch, the second ball valve is disposed in the second branch tocontrol a gas flow through the second branch.
 20. The ventilator ofclaim 19, further comprising an air entrainment device in fluidcommunication with the tubing, wherein the air entrainment device isconfigured to entrain the input gas.